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

0,3

Comments

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

Links

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

Formula

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

Example

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

Mathematica

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

Prog

(Magma) [Seqint(Reverse(Intseq(2^n-1))): n in [0..40]];
(PARI) a(n) = eval(concat(Vecrev(Str(2^n-1)))) \\ Felix Fröhlich, Jul 03 2016

Crossrefs

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

Sequence in context: A113775 A113236 A035499 * A120788 A346143 A207138

Adjacent sequences: A273089 A273090 A273091 * A273093 A273094 A273095

Keyword

nonn,base,easy

Author

Vincenzo Librandi, May 15 2016

Status

approved