A104499 Primes by index in A001945.

4, 6, 8, 9, 10, 11, 15, 17, 19, 23, 25, 31, 41, 47, 59, 61, 71, 113, 127, 137, 157, 167, 223, 401, 443, 457, 503, 523, 619, 701, 859, 991, 1021, 1187, 1217, 1223, 1361, 1847, 1867, 2237, 2579, 2693, 3313, 4219, 4931, 4967, 5413, 7727, 8011, 8387, 8761, 11083, 13781, 16871, 23311, 28661, 28871, 29123

Offset: 1

Author

Robert G. Wilson v, Mar 10 2005

Keywords

• nonn

Comments

All terms greater than a(11)=25 are prime so far.

a(80) > 10^6. - Paul Vanderveen, Oct 02 2022

Links

• Paul Vanderveen, Table of n, a(n) for n = 1..79

Crossrefs

Cf. A001945.

Programs

Haskell

import Data.List (findIndices)
a104499 n = a104499_list !! (n-1)
a104499_list = findIndices ((== 1) . a010051) a001945_list
-- Reinhard Zumkeller, Jan 11 2012

Mathematica

a[0] = 0; a[1] = a[2] = a[3] = a[5] = 1; a[4] = 5; a[n_] := a[n] = -a[n - 1] + a[n - 2] + 3a[n - 3] + a[n - 4] - a[n - 5] - a[n - 6]; lst = {}; Do[ If[ PrimeQ[a [ n]], AppendTo[lst, n]], {n, 21900}]; lst

Formula

A001945(a(n+1)) = A204138(n). [Reinhard Zumkeller, Jan 11 2012]

Extensions

a(50) and a(52) corrected and more terms from Paul Vanderveen, Jul 27 2022