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A216907 Smallest palindromic number of length 13 in two bases differing by n. 15

%I #16 Aug 22 2015 00:49:52

%S 318713056300,101252880671531,778061547945037,8047782883062742,

%T 37866346844745025,247644110790746909,828823170233185174,

%U 10556938000726441969,10175119610486126649,34575397981277771773,91506808775956056797

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

%C 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.

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

%Y 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.

%K nonn,base

%O 1,1

%A _James G. Merickel_, Sep 19 2012

%E a(10) added by _James G. Merickel_, Oct 17 2012

%E a(11) from _Chai Wah Wu_, Aug 20 2015

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Last modified March 28 05:39 EDT 2024. Contains 371235 sequences. (Running on oeis4.)