A216907 Smallest palindromic number of length 13 in two bases differing by n.

318713056300, 101252880671531, 778061547945037, 8047782883062742, 37866346844745025, 247644110790746909, 828823170233185174, 10556938000726441969, 10175119610486126649, 34575397981277771773, 91506808775956056797

Offset

1,1

Comments

See comments sections of A216840 and A216841. Smallest of pair of bases are 8, 12, 14, 17, 19, 22, 24, 30, 32. For the remarkable case a(10), not only does the number have four 7s in a row in base 10, but it also has prime reversal there and in its 2nd base of 13-palindromicity, 42, no digit larger than 20 appears. A216*** cross-references are others in a collection of sequences that includes this one, while A171*** ones are various record multi-base palindromes.

Links

Table of n, a(n) for n=1..11.

Example

The first term is 4506461646054 in base 8 and 1113578753111 in base 9.

Crossrefs

Cf. A171701, A171702, A171703, A171704, A171705, A171706, A171740, A171741, A171742, A171775, A216840, A216841, A216843, A216899, A216900, A216901, A216902, A216903, A216904, A216905, A216906, A216908, A216909, A216910.

Sequence in context: A172847 A354071 A022263 * A186911 A340155 A172714

Adjacent sequences: A216904 A216905 A216906 * A216908 A216909 A216910

Keyword

nonn,base

Author

James G. Merickel, Sep 19 2012

Extensions

a(10) added by James G. Merickel, Oct 17 2012

a(11) from Chai Wah Wu, Aug 20 2015

Status

approved