This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A307001 #32 Jan 25 2022 17:35:20
%S A307001 3,5,7,9,13,15,17,21,23,25,29,31,37,39,41,45,49,53,55,57,63,65,69,71,
%T A307001 73,77,79,81,85,93,95,97,101,105,109,111,119,121,125,129,133,135,137,
%U A307001 141,143,149,151,153,157,161,169,175,177,181,183,185,189,193,197
%N A307001 Odd numbers > 1 not of the form (3n*k - n - k + 1)/2 where n and k are odd numbers > 1.
%C A307001 Terms are the odd numbers > 1 not appearing in array A322744 with its first row and column omitted.
%C A307001 They are the odd numbers in A307002. - _David Lovler_, Jan 17 2022
%t A307001 Select[2 Range[100]-1, FindInstance[# == 1 + 2*n + k (2 + 6 n) && n>0 && k>0, {n,k}, Integers] === {} &] (* _Giovanni Resta_, May 06 2019 *)
%o A307001 (PARI) isok(n) = {my(kj, tij); if (n % 2, forstep (i=3, oo, 2, kj = 0; forstep (j=3, i, 2, tij = (3*i*j - i - j +1)/2; if (tij == n, return (0)); if (tij > n, kj = j; break);); if ((kj == 3) && (tij > n), break);); return (n>1));} \\ _Michel Marcus_, Apr 24 2019 and Jan 25 2022
%Y A307001 Cf. A322744, A307002.
%K A307001 nonn,easy
%O A307001 1,1
%A A307001 _David Lovler_, Mar 19 2019
%E A307001 Definition amended by _David Lovler_, Jan 25 2022