A055483 -id:A055483 - cp's OEIS frontend

A072051 Smallest k such that gcd(k, reverse(k)) = 11^n.

11, 121, 1331, 14641, 121110352, 1332213872, 105923336431682, 4676049710123077, 36606937477221265, 30983951005022964839, 1365869521861436622239

Offset: 1

Labos Elemer, Jun 10 2002

			a(8) = 4676049710123077 = (11^8)*13*1678009, reverse(a(8)) = 7703210179406764 = (11^8)*2*2*157*57223.

Cf. A004086, A055483, A069554, A071686 (=2^n), A072005 (=3^n), A072021 (=5^n), A072050 (=7^n).

a(n) = A069554(11^n).

a(9)-a(11) from Sean A. Irvine, Sep 02 2024

A175823 Numbers k such that gcd(k^2, reverse(k^2)) = k.

Original entry on oeis.org

1, 9, 297, 513, 783, 999, 1323, 1331, 4961, 10989, 11979, 12969, 14733, 20402, 29088, 89109, 99999, 109989, 122221, 188887, 210789, 218097, 377199, 477773, 483516, 525503, 718189, 1099989, 2128806, 2920819, 7769223, 9999999, 10999989, 12222221, 19097181, 21510896

Offset: 1

Michel Lagneau, Sep 13 2010

			297 is in the sequence, because 297^2 = 88209, and reverse(88209) = 90288 = 297*304.

Cf. A004086, A055483.

Select[Range[5000000], GCD[FromDigits[Reverse[IntegerDigits[(#)^2 ]]],#^2]==# &]

isok(k) = gcd(k^2, fromdigits(Vecrev(digits(k^2)))) == k; \\ Amiram Eldar, May 24 2025

More terms from Amiram Eldar, May 24 2025

cp's OEIS Frontend

A072051 Smallest k such that gcd(k, reverse(k)) = 11^n.

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