A273092 a(n) = 2^n - 1 written backwards.

0, 1, 3, 7, 51, 13, 36, 721, 552, 115, 3201, 7402, 5904, 1918, 38361, 76723, 53556, 170131, 341262, 782425, 5758401, 1517902, 3034914, 7068838, 51277761, 13445533, 36880176, 727712431, 554534862, 119078635, 3281473701, 7463847412, 5927694924, 1954399858

Offset: 0

Author

Vincenzo Librandi, May 15 2016

Keywords

• nonn
• base
• easy

Comments

Reverse primes in this sequence (3, 7, 31, 127, 2047, 8191, 131071, 524287, 8388607 etc) are Mersenne primes.

Examples

			For n = 8, 2^n - 1 = 255, so 552 is in the sequence. - _Michael B. Porter_, Jul 02 2016
		

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Crossrefs

Cf. A000225, A001348, A004086, A004087, A135623.

Programs

Magma

[Seqint(Reverse(Intseq(2^n-1))): n in [0..40]];

Mathematica

Table[FromDigits[Reverse[IntegerDigits[2^n-1]]], {n, 0, 75}]

PARI

a(n) = eval(concat(Vecrev(Str(2^n-1)))) \\ Felix Fröhlich, Jul 03 2016

Formula

a(n) = A004086(A000225(n)).