A244930 Indices of primes in A214831.

3, 4, 7, 8, 16, 26, 34, 42, 78, 94, 101, 107, 216, 255, 543, 562, 851, 981, 1099, 1528, 1824, 1955, 2122, 2488, 2500, 15331, 15961, 24107, 24938, 26051, 58504, 61617, 81034, 85119, 89768, 90597, 97191, 116899, 195346

Offset

1,1

Comments

a(40) > 2*10^5.

Links

Table of n, a(n) for n=1..39.

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, 9, 9}; For[n=3, n<=1000, n++, sum=Plus@@a; If[PrimeQ[sum], Print[n]]; a=RotateLeft[a]; a[[3]]=sum]
Flatten[Position[LinearRecurrence[{1, 1, 1}, {1, 9, 9}, 200000], _?PrimeQ]]-1 (* The prime number at index 195346 (term a(39) of this sequence) has 51699 digits, so this program takes a long time to run. *) (* Harvey P. Dale, Dec 29 2019 *)

Crossrefs

Cf. A001590, A100683, A231574, A231575, A232542, A214899, A230607, A020992, A232498, A214727, A081172, A214752, A141523, A214825, A235862, A214827, A214828, A214829, A243622, A243623, A214831.

Sequence in context: A306612 A117587 A359747 * A130420 A214096 A169943

Adjacent sequences: A244927 A244928 A244929 * A244931 A244932 A244933

Keyword

nonn

Author

Robert Price, Jul 08 2014

Status

approved