login
A114419
a(n) is the smallest number k such that Fibonacci(k) is a multiple of primorial(n).
2
3, 12, 60, 120, 120, 840, 2520, 2520, 2520, 2520, 2520, 47880, 47880, 526680, 1053360, 3160080, 91642320, 91642320, 1557919440, 1557919440, 57643019280, 749359250640, 749359250640, 749359250640, 5245514754480, 26227573772400
OFFSET
1,1
COMMENTS
Because the Fibonacci numbers form a divisibility sequence, each term of this sequence is a multiple of the previous term. The multiple can be computed using A001602. - T. D. Noe, May 04 2009
FORMULA
a(n) = {min j: A002110(n) | A000045(j)}. - R. J. Mathar, Jan 31 2008
a(n) = lcm(A001602(1),...,A001602(n)). - T. D. Noe, May 04 2009
EXAMPLE
a(2)=12 because 12th Fibonacci number (144) is the smallest Fibonacci number which is a multiple of primorial(2), i.e., 6.
PROG
(PARI) a(n) = {prn = prod(k=1, n, prime(k)); k = 1; while(fibonacci(k) % prn, k++); k; } \\ Michel Marcus, Jan 13 2016
CROSSREFS
Cf. A267095.
Sequence in context: A277179 A201013 A065080 * A090830 A233283 A376247
KEYWORD
nonn
AUTHOR
Shyam Sunder Gupta, Feb 12 2006
EXTENSIONS
a(1) corrected and a(14) added by R. J. Mathar, Jan 31 2008
a(14)-a(18) from Donovan Johnson, Sep 03 2008
Extended by T. D. Noe, May 04 2009
STATUS
approved