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A131788 a(n) = a(n-1) + (sum of the terms, from among the first (n-1) terms of the sequence, which are coprime to the n-th Fibonacci number). 1
1, 2, 3, 6, 18, 22, 74, 173, 350, 627, 1903, 3980, 11139, 29437, 72720, 108312, 337079, 379735, 988163, 1354929, 4458118, 12200929, 32148649, 78234718, 208109020, 546549127, 1108402372, 3055896646, 8105184898, 8151267237, 29457007624 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..31.

EXAMPLE

The 6th Fibonacci number is 8. Of the first 5 terms, only terms a(1)=1 and a(3)=3 are coprime to 8. So a(6) = a(5) + 1 + 3 = 22.

MAPLE

with(combinat): a[1] := 1: for n from 2 to 30 do s := 0: for j to n-1 do if gcd(a[j], fibonacci(n)) = 1 then s := s+a[j] else s := s end if end do: a[n] := a[n-1]+s end do: seq(a[n], n = 1 .. 30); # Emeric Deutsch, Jul 17 2007

CROSSREFS

Cf. A131787.

Sequence in context: A169974 A003183 A213616 * A294455 A277703 A080338

Adjacent sequences:  A131785 A131786 A131787 * A131789 A131790 A131791

KEYWORD

nonn

AUTHOR

Leroy Quet, Jul 15 2007

EXTENSIONS

More terms from Emeric Deutsch and Joshua Zucker, Jul 17 2007

STATUS

approved

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Last modified August 12 23:19 EDT 2020. Contains 336440 sequences. (Running on oeis4.)