A027571 Numbers k such that k^2 + (k+1)^2 is palindromic.

0, 1, 9, 12, 16, 919, 1257, 1262, 1621, 1706, 170706, 904280, 1258182, 7901014, 8659929, 12458597, 17070706, 80472264, 1616689803, 1680689788, 1705387643, 7360311900, 8032814139, 8055329360, 12574461617, 16794058711, 165058650666, 844706005220, 1250999800012, 1255589965852

Offset

1,3

Comments

a(50) > 70710678118654752440. - Patrick De Geest, May 25 2021

Links

Patrick De Geest, Table of n, a(n) for n = 1..49 (terms a(1)..a(29) from Giovanni Resta)

Patrick De Geest, Palindromic Sums of Squares of Consecutive Integers

Patrick De Geest, Palindromic Centered Polygonal Numbers

Prog

(PARI) isok(m) = my(d=digits(m^2+(m+1)^2)); d == Vecrev(d); \\ Michel Marcus, Jan 05 2019

Crossrefs

Cf. A001844, A027572, A050236, A050239.

A050236 is a subsequence.

Sequence in context: A084375 A076674 A176062 * A342757 A154631 A199593

Adjacent sequences: A027568 A027569 A027570 * A027572 A027573 A027574

Keyword

nonn,base

Author

Patrick De Geest

Extensions

a(18)-a(21) from Donovan Johnson, Aug 26 2012

a(22)-a(29) from Giovanni Resta, Aug 06 2019

a(1)=0 added by Patrick De Geest, May 25 2021

Status

approved