OFFSET

1,3

COMMENTS

Is this sequence finite?

No other terms < 10^32. - Michael S. Branicky, Jul 12 2022

EXAMPLE

196 is a term because 196 = 14^2 is a perfect square and 196 = 6*(6+1)*(5*6-2)/6 is the 6th heptagonal pyramidal number.

MAPLE

select(issqr, [seq(n*(n+1)*(5*n-2)/6, n=0..50)])[]; # Alois P. Heinz, Apr 21 2022

MATHEMATICA

Select[Table[n*(n + 1)*(5*n - 2)/6, {n, 0, 100}], IntegerQ @ Sqrt[#] &] (* Amiram Eldar, Apr 21 2022 *)

CROSSREFS

KEYWORD

nonn,more

AUTHOR

Kelvin Voskuijl, Apr 21 2022

STATUS

approved