A247561 Indices of primes in the tetranacci sequence A000288.

5, 6, 10, 11, 12, 13, 18, 30, 31, 36, 38, 97, 108, 150, 196, 221, 277, 532, 596, 2468, 2691, 3773, 4303, 5755, 8925, 10083, 11708, 14080, 19990, 24102, 34767, 35973, 39238, 49760, 97706

Offset

1,1

Comments

a(36) > 2*10^5.

Links

Table of n, a(n) for n=1..35.

Tony D. Noe and Jonathan Vos Post, Primes in Fibonacci n-step and Lucas n-step Sequences, J. of Integer Sequences, Vol. 8 (2005), Article 05.4.4

Mathematica

a={1, 1, 1, 1}; For[n=4, n<=1000, n++, sum=Plus@@a; If[PrimeQ[sum], Print[n]]; a=RotateLeft[a]; a[[4]]=sum]
Flatten[Position[LinearRecurrence[{1, 1, 1, 1}, {1, 1, 1, 1}, 10^5], _?PrimeQ]]- 1 (* Harvey P. Dale, Dec 20 2016 *)

Crossrefs

Cf. A001590, A001631, A100683, A231574, A231575, A232542, A214899, A230607, A020992, A232498, A214727, A081172, A214752, A141523, A214825, A235862, A000288.

Sequence in context: A191472 A189056 A340325 * A273401 A042958 A265188

Adjacent sequences: A247558 A247559 A247560 * A247562 A247563 A247564

Keyword

nonn,more

Author

Robert Price, Sep 27 2014

Status

approved