



1, 6, 10, 14, 18, 22, 26, 30, 34, 38, 42, 46, 50, 54, 58, 62, 66, 70, 74, 78, 82, 86, 90, 94, 98, 102, 106, 110, 114, 118, 122, 126, 130, 134, 138, 142, 146, 150, 154
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OFFSET

1,2


COMMENTS

It appears this sequence gives the positive integers m such that the sum of the first m Fibonacci numbers divides their product. For example, if n=2 and m=a(2)=6, we have the sum 1+1+2+3+5+8=20 which clearly divides the corresponding product 480. See A175553 for the analogous sequence when using the triangular numbers. Sum[Fibonacci[k],{k,1,n}] divides Product[Fibonacci[k],{k,1,n}]: [From John W. Layman, Jul 10 2010]


LINKS

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


FORMULA

Inverse binomial transform of A003261: (1, 7, 23, 63, 159, 383,...). Binomial transform of [1, 5, 1, 1, 1, 1,...]. "1" followed by 2 * [3, 5, 7, 9, 11,...].
O.g.f.: x(1+4xx^2)/(1x)^2. a(n)=4n2, n>1.  R. J. Mathar, Jun 08 2008
1/(1+1/(6+1/(10+1/(14+1/(...(continued fraction)))))) = (e1)/2 with e = 2.718281... Philippe Deléham, Mar 09 2013


EXAMPLE

a(4) = 14 = (1, 3, 3, 1) dot (1, 5, 1, 1) = (1, 15, 3, 1).


CROSSREFS

Cf. A003261.
Cf. A175553. [From John W. Layman, Jul 10 2010]
Sequence in context: A091577 A115036 A315169 * A073760 A315170 A315171
Adjacent sequences: A133650 A133651 A133652 * A133654 A133655 A133656


KEYWORD

nonn


AUTHOR

Gary W. Adamson, Sep 19 2007


EXTENSIONS

More terms from R. J. Mathar, Jun 08 2008


STATUS

approved



