A090208 Sums of two consecutive nonprime Fibonacci numbers (A090206).

1, 2, 9, 29, 55, 89, 199, 521, 987, 1597, 3571, 6765, 10946, 17711, 28657, 64079, 121393, 196418, 317811, 514229, 1149851, 2178309, 3524578, 5702887, 9227465, 14930352, 24157817, 39088169, 63245986, 102334155, 165580141, 267914296, 433494437, 969323029, 1836311903

Offset

1,2

Links

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

Formula

a(n) = A090206(n) + A090206(n+1). - Georg Fischer, Jan 11 2026

Example

A090206(1..5) = (0, 1, 1, 8, 21) -> a(1..4) = (1, 2, 9, 29).

Mathematica

Total /@ Partition[ Select[Fibonacci /@ Range[0, 40], ! PrimeQ[#] &], 2, 1] (* Seth A. Troisi, May 14 2022 *)

Crossrefs

Cf. A000045, A090206.

Sequence in context: A110377 A338436 A041877 * A123058 A212272 A062452

Adjacent sequences: A090205 A090206 A090207 * A090209 A090210 A090211

Keyword

nonn,easy,less

Author

Felix Tubiana, Jan 22 2004

Extensions

a(29) corrected by Seth A. Troisi, May 13 2022

Edited by Georg Fischer, Jan 11 2026

Status

approved