

A263619


Number of palindromic squares with at most n digits.


2



4, 4, 7, 7, 14, 15, 20, 20, 31, 31, 36, 37, 56, 56, 69, 70, 95, 95, 113, 113
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,1


COMMENTS

Partial sums of A263618.


LINKS

Table of n, a(n) for n=1..20.
G. J. Simmons, Palindromic powers, J. Rec. Math., 3 (No. 2, 1970), 9398. [Annotated scanned copy] See page 95.


MATHEMATICA

Table[Length[Select[Range[0, Floor[Sqrt[10^n]]], PalindromeQ[#^2] &]], {n, 10}] (* Robert Price, Apr 26 2019 *)


CROSSREFS

Cf. A002778, A002779, A263617, A263617, A263618, A263620.
Sequence in context: A168233 A238391 A049647 * A046538 A353713 A107432
Adjacent sequences: A263616 A263617 A263618 * A263620 A263621 A263622


KEYWORD

nonn,base,more


AUTHOR

N. J. A. Sloane, Oct 23 2015


EXTENSIONS

a(13)a(19) from Chai Wah Wu, Oct 24 2015
a(20) from Robert Price, Apr 26 2019


STATUS

approved



