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

1,1

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

Formula

A001945(a(n+1)) = A204138(n). [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

Prog

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

Crossrefs

Cf. A001945.

Sequence in context: A299540 A085558 A084984 * A338941 A137353 A336371

Adjacent sequences: A104496 A104497 A104498 * A104500 A104501 A104502

Keyword

nonn

Author

Robert G. Wilson v, Mar 10 2005

Extensions

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

Status

approved