OFFSET
1,2
COMMENTS
Intersection of A000566 and A008589. Their indices are given by A047352. - Michel Marcus, Feb 27 2014
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
MATHEMATICA
Select[PolygonalNumber[7, Range[0, 200]], Divisible[#, 7]&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Dec 02 2019 *)
PROG
(PARI) isok(n) = ispolygonal(n, 7) && !(n % 7); \\ Michel Marcus, Feb 27 2014
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Luc Stevens (lms022(AT)yahoo.com), Apr 29 2006
STATUS
approved