OFFSET
1,1
LINKS
Eric Weisstein's World of Mathematics, Figurate Number.
MATHEMATICA
nxt[{n_, a_}] := {n + 1, a + Prime[n + 1] (2 n + 1)}; NestList[nxt, {1, 2}, 50][[All, 2]]+1 (* Harvey P. Dale, Jul 05 2018 *)
PROG
(PARI) a(n) = 1 + sum(i=1, n, prime(i)*(2*i-1)); \\ Michel Marcus, Jan 22 2022
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Jun 01 2003
EXTENSIONS
Definition corrected by Harvey P. Dale, Jul 03 2018
STATUS
approved