OFFSET
1,2
COMMENTS
If it exists, a(5) > 10^29. - Bert Dobbelaere, Apr 12 2019
LINKS
Eric Weisstein's World of Mathematics, Centered Square Number
Eric Weisstein's World of Mathematics, Square Pyramidal Number
MATHEMATICA
csQ[n_] := IntegerQ[Sqrt[2*n-1]]; Select[Table[n(n+1)(2n+1)/6, {n, 0, 1000}], csQ] (* Amiram Eldar, Apr 11 2019 *)
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Ilya Gutkovskiy, Apr 10 2019
STATUS
approved