login
A104577
Indices of prime generalized tetranacci numbers, A073817.
5
2, 3, 8, 9, 16, 19, 24, 27, 46, 68, 71, 78, 107, 198, 309, 377, 477, 1057, 1631, 2419, 3974, 4293, 8247, 10513, 10709, 12011, 15042, 30543, 31607, 39664, 47552, 145858
OFFSET
1,1
COMMENTS
The sequence of generalized tetranacci numbers is defined as beginning with 1, 3, 7, 15. Subsequent terms are the sum of the previous four terms. Note that the sequence of these generalized tetranacci numbers has many more primes than the tetranacci sequence A000078 (whose prime indices are in A104534).
LINKS
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, 4}; Do[s=Plus@@a; a=RotateLeft[a]; a[[4]]=s; If[PrimeQ[s], Print[n]], {n, 30000}]
CROSSREFS
Cf. A104576 (indices of prime generalized tribonacci numbers).
Sequence in context: A331821 A093765 A260020 * A372824 A309017 A376191
KEYWORD
nonn
AUTHOR
T. D. Noe, Mar 16 2005
STATUS
approved