OFFSET
1,2
COMMENTS
LINKS
Daniel Starodubtsev, Table of n, a(n) for n = 1..10000
MATHEMATICA
Select[Table[PolygonalNumber[20, n], {n, 0, 200}], Divisible[#, 20] &] (* Amiram Eldar, Mar 22 2021 *)
PROG
(PARI) isok(n) = ispolygonal(n, 20) && !(n % 20); \\ Michel Marcus, Feb 27 2014
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Luc Stevens (lms022(AT)yahoo.com), Apr 29 2006
STATUS
approved