

A052057


Numbers k such that the decimal expansion of 2^k contains no palindromic substring except single digits.


2



0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 20, 21, 22, 29, 37, 54
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OFFSET

1,3


COMMENTS

Sequence is probably finite. Next term, if it exists, exceeds 1170.
Next term, if it exists, exceeds 50000.  Sean A. Irvine, Oct 18 2021


LINKS

Table of n, a(n) for n=1..22.


EXAMPLE

Record number is 2^54 = 18014398509481984.


MATHEMATICA

Select[Range[0, 10^3], NoneTrue[DeleteCases[Subsequences@ IntegerDigits[2^#], _?(Length[#] <= 1 &)], PalindromeQ] &] (* Michael De Vlieger, Oct 18 2021 *)


CROSSREFS

Cf. A000079, A050723, A052058, A052059.
Sequence in context: A341750 A246096 A098314 * A252493 A005496 A052060
Adjacent sequences: A052054 A052055 A052056 * A052058 A052059 A052060


KEYWORD

nonn,base,more


AUTHOR

Patrick De Geest, Jan 15 2000


EXTENSIONS

Edited by Jon E. Schoenfield, Oct 17 2019


STATUS

approved



