OFFSET
1,1
COMMENTS
Terms are the odd numbers > 1 not appearing in array A322744 with its first row and column omitted.
They are the odd numbers in A307002. - David Lovler, Jan 17 2022
MATHEMATICA
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 *)
PROG
(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
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
David Lovler, Mar 19 2019
EXTENSIONS
Definition amended by David Lovler, Jan 25 2022
STATUS
approved