Language: C

i,z=151201;main(j,n){table[z];for(;i<54;i++)for(j=0;j<54;j++)if((n=i*i*i+j*(j+1)*(j+2)/6)<z)table[n]=1;for(;scanf("%d",&n),n;printf("%d\n",n))while(!table[n])n--;}

Compiler output:
main.c:1:1: warning: data definition has no type or storage class
    1 | i,z=151201;main(j,n){table[z];for(;i<54;i++)for(j=0;j<54;j++)if((n=i*i*i+j*(j+1)*(j+2)/6)<z)table[n]=1;for(;scanf("%d",&n),n;printf("%d\n",n))while(!table[n])n--;}
      | ^
main.c:1:1: error: type defaults to 'int' in declaration of 'i' [-Wimplicit-int]
main.c:1:3: error: type defaults to 'int' in declaration of 'z' [-Wimplicit-int]
    1 | i,z=151201;main(j,n){table[z];for(;i<54;i++)for(j=0;j<54;j++)if((n=i*i*i+j*(j+1)*(j+2)/6)<z)table[n]=1;for(;scanf("%d",&n),n;printf("%d\n",n))while(!table[n])n--;}
      |   ^
main.c:1:12: error: return type defaults to 'int' [-Wimplicit-int]
    1 | i,z=151201;main(j,n){table[z];for(;i<54;i++)for(j=0;j<54;j++)if((n=i*i*i+j*(j+1)*(j+2)/6)<z)table[n]=1;for(;scanf("%d",&n),n;printf("%d\n",n))while(!table[n])n--;}
      |            ^~~~
main.c: In function 'main':
main.c:1:12: error: type of 'j' defaults to 'int' [-Wimplicit-int]
main.c:1:12: error: type of 'n' defaults to 'int' [-Wimplicit-int]
main.c:1:22: error: 'table' undeclared (first use in this function)
    1 | i,z=151201;main(j,n){table[z];for(;i<54;i++)for(j=0;j<54;j++)if((n=i*i*i+j*(j+1)*(j+2)/6)<z)table[n]=1;for(;scanf("%d",&n),n;printf("%d\n",n))while(!table[n])n--;}
      |                      ^~~~~
main.c:1:22: note: each undeclared identifier is reported only once for each function it appears in
main.c:1:109: error: implicit declaration of function 'scanf' [-Wimplicit-function-declaration]
    1 | i,z=151201;main(j,n){table[z];for(;i<54;i++)for(j=0;j<54;j++)if((n=i*i*i+j*(j+1)*(j+2)/6)<z)table[n]=1;for(;scanf("%d",&n),n;printf("%d\n",n))while(!table[n])n--;}
      |                                                                                                             ^~~~~
main.c:1:1: note: include '<stdio.h>' or provide a declaration of 'scanf'
  +++ |+#include <stdio.h>
    1 | i,z=151201;main(j,n){table[z];for(;i<54;i++)for(j=0;j<54;j++)if((n=i*i*i+j*(j+1)*(j+2)/6)<z)table[n]=1;for(;scanf("%d",&n),n;printf("%d\n",n))while(!table[n])n--;}
main.c:1:109: warning: incompatible implicit declaration of built-in function 'scanf' [-Wbuiltin-declaration-mismatch]
    1 | i,z=151201;main(j,n){table[z];for(;i<54;i++)for(j=0;j<54;j++)if((n=i*i*i+j*(j+1)*(j+2)/6)<z)table[n]=1;for(;scanf("%d",&n),n;printf("%d\n",n))while(!table[n])n--;}
      |                                                                                                             ^~~~~
main.c:1:109: note: include '<stdio.h>' or provide a declaration of 'scanf'
main.c:1:126: error: implicit declaration of function 'printf' [-Wimplicit-function-declaration]
    1 | i,z=151201;main(j,n){table[z];for(;i<54;i++)for(j=0;j<54;j++)if((n=i*i*i+j*(j+1)*(j+2)/6)<z)table[n]=1;for(;scanf("%d",&n),n;printf("%d\n",n))while(!table[n])n--;}
      |                                                                                                                              ^~~~~~
main.c:1:126: note: include '<stdio.h>' or provide a declaration of 'printf'
main.c:1:126: warning: incompatible implicit declaration of built-in function 'printf' [-Wbuiltin-declaration-mismatch]
main.c:1:126: note: include '<stdio.h>' or provide a declaration of 'printf'