login
Palindromic heptagonal numbers.
6

%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