A180453 Numbers that are 4-digit palindromes in at least 2 bases.

624, 910, 2000, 2124, 3663, 4920, 6120, 6750, 6776, 7056, 8008, 8778, 9520, 10248, 11052, 13320, 13500, 14112, 14376, 15561, 16660, 16842, 17520, 18226, 19040, 19782, 21945, 22104, 22656, 22708, 23982, 26752, 27302, 27650, 27870, 28200

Offset

1,1

Links

Table of n, a(n) for n=1..36.

Example

624 = 4444_5 = 1551_7.
19040 is a four-digit palindrome in bases 13, 15, and 19:  19040 = 8888_13 = 5995_15 = {2,14,14,2}_19.

Prog

(PARI) isok(m) = {my(nb = 0); for (b=2, m-1, my(d=digits(m, b)); if ((#d == 4) && (Vecrev(d) == d), nb++); if (nb == 2, return (1)); ); } \\ Michel Marcus, Feb 13 2021

Crossrefs

Cf. A180454.

Sequence in context: A345546 A345799 A035479 * A216843 A043368 A158374

Adjacent sequences: A180450 A180451 A180452 * A180454 A180455 A180456

Keyword

nonn,base

Author

John L. Drost, Sep 05 2010

Status

approved