%I #15 Aug 11 2024 14:41:32
%S 0,1,7,55,616,3553,4774,60606,848848,4615164,5400045,6050506,
%T 7165445617,62786368726,65331413356,73665056637,91120102119,
%U 345546645543,365139931563,947927729749,3646334336463,7111015101117,717685292586717,19480809790808491
%N Palindromic heptagonal numbers.
%C Intersection of A002113 (palindromic) and A000566 (heptagonal).
%H Robert Price, <a href="/A054910/b054910.txt">Table of n, a(n) for n = 1..29</a>
%H P. De Geest, <a href="https://www.worldofnumbers.com/hepta.htm">Palindromic Heptagonals</a>
%t Select[PolygonalNumber[7, Range[0, 10^6]], PalindromeQ] (* _Robert Price_, Apr 28 2019 *)
%Y Cf. A054971, A000566.
%K nonn,base
%O 1,3
%A _Jeff Heleen_, May 26 2000
%E Added a(1)=0 by _Robert Price_, Apr 28 2019