A117772 Total number of palindromic primes in base 2 below 2^n.

0, 1, 3, 3, 5, 5, 8, 8, 11, 11, 18, 18, 30, 30, 53, 53, 93, 93, 187, 187, 329, 329, 600, 600, 1080, 1080, 1936, 1936, 3657, 3657, 6756, 6756, 12328, 12328, 23127, 23127, 43909, 43909, 83377, 83377, 156049, 156049, 295916, 295916, 570396, 570396, 1090772

Offset

1,3

Comments

Every palindrome with an even number of digits is divisible by 11 (in base 2) and therefore is composite (not prime). Hence there is only one palindromic prime with an even number of digits, namely 11_2 = 3_{10}.

Links

Martin Raab, Table of n, a(n) for n = 1..66

Eric Weisstein: Palindromic Prime.

Crossrefs

Cf. A016041, A117697.

Sequence in context: A308415 A063281 A362059 * A026924 A240313 A275369

Adjacent sequences: A117769 A117770 A117771 * A117773 A117774 A117775

Keyword

nonn,base

Author

Martin Renner, Apr 15 2006

Extensions

a(23)-a(40) from Donovan Johnson, Dec 02 2009

Extended to a(66) by Martin Raab, Oct 20 2015

Status

approved