OFFSET
1,1
COMMENTS
Conjecture: All odd numbers d >= 17 excluding d in {P_s(k), s >= 3, k >= 5; P_s(k) - 1, s >= 3, k >= 4; a(n)} are accurate the primes p = d >= 17.
MATHEMATICA
pn[s_, k_] := s (k - 1) k/2 - (k - 1)^2 + 1;
lst = {}; Do[n = (pn[s, k] + 1) (pn[ss, ks] + 1);
lst = Union[lst, {n}], {s, 3, 20}, {ss, 3, 20}, {k, 3, 4}, {ks, 3,
4}]; Take[lst, 70]
CROSSREFS
KEYWORD
nonn
AUTHOR
Ralf Steiner, Jul 10 2018
STATUS
approved