A139483 -id:A139483 - cp's OEIS frontend

A139484 Indices of Mersenne primes among primes of the form 24k + 7 (A107006).

1, 2, 5, 129, 1536, 5430, 13138099

Offset: 2

Artur Jasinski, Apr 23 2008

All Mersenne primes with the exception of the first one (3) are of the form 24*k + 7.

Sequence lists indices m where A139483(m) is a Mersenne prime.

			5 is in this sequence, because A107006(5) is a Mersenne prime.

Cf. A107006, A124477, A139479, A139483.

w = {2, 3, 5, 7, 13, 17, 19, 31, 61, 89, 107, 127, 521, 607}; Do[w[[n]] = 2^w[[n]] - 1, {n, 1, Length[w]}]; c = 0; a = {}; Do[k = 24 n + 7; If[PrimeQ[k], c = c + 1; If[MemberQ[w, k], AppendTo[a, c]]], {n, 1, 10000000}]; a
With[{mps=2^#-1&/@MersennePrimeExponent[Range[20]]},Position[ Select[ 24*Range[0,10^8]+7,PrimeQ],?(MemberQ[mps,#]&)]]//Flatten (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale, Aug 20 2019 *)

Edited name and added example by Dmitry Kamenetsky, Jan 02 2011

a(8) from Charles R Greathouse IV, Mar 22 2011

A139527 Numbers n such that numbers 24n+5 are primes.

Original entry on oeis.org

0, 1, 2, 4, 6, 7, 8, 11, 12, 13, 16, 19, 21, 23, 27, 28, 29, 32, 33, 34, 39, 42, 44, 46, 49, 51, 53, 54, 57, 62, 67, 68, 71, 72, 78, 79, 81, 82, 83, 86, 89, 92, 93, 96, 97, 98, 99, 103, 106, 109, 112, 114, 116, 118, 119, 121, 123, 134, 141, 142, 144, 147, 148, 149, 153, 154

Offset: 1

Artur Jasinski, Apr 25 2008

nonn

Numbers n such that:
24n+1 is prime see A111174, primes 24n+1 see A107008
24n+5 is prime see A139527, primes 24n+5 see A107003
24n+7 is prime see A139483, primes 24n+7 see A107006
24n+11 is prime A139528, primes 24n+11 see A107007
24n+13 is prime see A139529, primes 24n+13 see A139530
24n+17 is prime see A139531, primes 24n+17 see A107181
24n+19 is prime see A139532, primes 24n+19 see A141373
24n+23 is prime see A131210, primes 24n+23 see A134517

Harvey P. Dale, Table of n, a(n) for n = 1..1000

a = {}; Do[If[PrimeQ[24 n + 5], AppendTo[a, n]], {n, 0, 200}]; a
Select[Table[(Prime[n]-5)/24,{n,800}],IntegerQ] (* Harvey P. Dale, Feb 25 2016 *)

cp's OEIS Frontend

A139484 Indices of Mersenne primes among primes of the form 24k + 7 (A107006).

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