C++, (削除) 63 (削除ここまで) 57 bytes
(-6 bytes thanks to AZTECCO)
[](int n){for(int i=n+3;i--;)n*=n!=-~i*i*~-i/6;return n;}
This swaps truthy/falsy, so it returns an integer greater than 0 for tetrahedralnon-tetrahedral numbers, and 0 for non-tetrahedraltetrahedral numbers.
63 byte version:
[](int n){for(int i=n+2;i-->0;)if(n==-~i*i*~-i/6)n=0;return n;}
C++, (削除) 63 (削除ここまで) 57 bytes
(-6 bytes thanks to AZTECCO)
[](int n){for(int i=n+3;i--;)n*=n!=-~i*i*~-i/6;return n;}
This swaps truthy/falsy, so it returns an integer greater than 0 for tetrahedral numbers, and 0 for non-tetrahedral numbers.
63 byte version:
[](int n){for(int i=n+2;i-->0;)if(n==-~i*i*~-i/6)n=0;return n;}
C++, (削除) 63 (削除ここまで) 57 bytes
(-6 bytes thanks to AZTECCO)
[](int n){for(int i=n+3;i--;)n*=n!=-~i*i*~-i/6;return n;}
This swaps truthy/falsy, so it returns an integer greater than 0 for non-tetrahedral numbers, and 0 for tetrahedral numbers.
63 byte version:
[](int n){for(int i=n+2;i-->0;)if(n==-~i*i*~-i/6)n=0;return n;}
C++, 63(削除) 63 (削除ここまで) 57 bytes
(-6 bytes thanks to AZTECCO)
[](int n){for(int i=n+2;ii=n+3;i-->0;;)if(n==n*=n!=-~i*i*~-i/6)n=0;return6;return n;}
This swaps truthy/falsy, so it returns an integer greater than 0 for tetrahedral numbers, and 0 for non-tetrahedral numbers.
63 byte version:
[](int n){for(int i=n+2;i-->0;)if(n==-~i*i*~-i/6)n=0;return n;}
C++, 63 bytes
[](int n){for(int i=n+2;i-->0;)if(n==-~i*i*~-i/6)n=0;return n;}
This swaps truthy/falsy, so it returns an integer greater than 0 for tetrahedral numbers, and 0 for non-tetrahedral numbers.
C++, (削除) 63 (削除ここまで) 57 bytes
(-6 bytes thanks to AZTECCO)
[](int n){for(int i=n+3;i--;)n*=n!=-~i*i*~-i/6;return n;}
This swaps truthy/falsy, so it returns an integer greater than 0 for tetrahedral numbers, and 0 for non-tetrahedral numbers.
63 byte version:
[](int n){for(int i=n+2;i-->0;)if(n==-~i*i*~-i/6)n=0;return n;}