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A181156 Odd Fibonacci numbers F which have a proper Fibonacci divisor G such that F/G is a Lucas number or a product of Lucas numbers. 1
3, 21, 55, 377, 987, 6765, 17711, 121393, 317811, 2178309, 5702887, 39088169, 102334155, 701408733, 1836311903, 12586269025, 32951280099, 225851433717, 591286729879, 4052739537881, 10610209857723, 72723460248141, 190392490709135, 1304969544928657, 3416454622906707 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

A conjectural statement that, for odd prime p, the ratio F_{p^2}/F_{p} is never a Lucas number or a product of some Lucas numbers, yields that

a) an odd Fibonacci number F is in the sequence iff for its maximal proper Fibonacci divisor G, we have: ind G does not equal sqrt(ind F) and F/G does not have a proper Fibonacci divisor > 3;

b) an odd Fibonacci number F is in the sequence iff its index has one of the forms: 6k+2 or 6k+4 (see A047235).

LINKS

Table of n, a(n) for n=1..25.

EXAMPLE

F = 3 has the proper Fibonacci divisor G=1, and F/G = 3 is a Lucas number.

F = 317811 has the proper Fibonacci divisors 3, 13, and 377, and F/377 = 843 is a Lucas number.

CROSSREFS

Cf. A000045, A000032, A014437, A014447.

Sequence in context: A152773 A039595 A033567 * A162394 A129212 A328042

Adjacent sequences:  A181153 A181154 A181155 * A181157 A181158 A181159

KEYWORD

nonn

AUTHOR

Vladimir Shevelev, Oct 07 2010

STATUS

approved

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Last modified November 21 04:33 EST 2019. Contains 329350 sequences. (Running on oeis4.)