

A007573


Number of asymmetric families of palindromic squares.
(Formerly M1319)


4



1, 2, 5, 6, 9, 10, 10, 15, 15, 16, 18, 24, 18, 26, 24, 30, 27, 33, 28, 40, 33, 40, 35, 48, 37, 50, 42, 53, 45
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OFFSET

7,2


REFERENCES

M. Keith, Classification and enumeration of palindromic squares, J. Rec. Math., 22 (No. 2, 1990), 124132.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).


LINKS

Table of n, a(n) for n=7..35.
P. De Geest, Subsets of Palindromic Squares
M. Keith, Classification and enumeration of palindromic squares, J. Rec. Math., 22 (No. 2, 1990), 124132. [Annotated scanned copy]. See foot of page 130.
G. J. Simmons, On palindromic squares of nonpalindromic numbers, J. Rec. Math., 5 (No. 1, 1972), 1119. [Annotated scanned copy]


EXAMPLE

Second term a(9)=2 indicates existence of two length 9 base numbers, 110091011 and 111091111.


CROSSREFS

Cf. A002778, A002779.
Sequence in context: A136369 A269472 A244272 * A285663 A143909 A284507
Adjacent sequences: A007570 A007571 A007572 * A007574 A007575 A007576


KEYWORD

nonn,base,changed


AUTHOR

Simon Plouffe, N. J. A. Sloane, Robert G. Wilson v


EXTENSIONS

a(21)a(35) from Sean A. Irvine, Jan 10 2018


STATUS

approved



