A081953 Smallest Fibonacci number equal one plus the product of n (not necessarily distinct) integers > 1.

3, 5, 13, 55, 1597, 28657, 28657, 121393, 2971215073, 2971215073, 2971215073, 7778742049, 308061521170129, 308061521170129, 135301852344706746049, 135301852344706746049, 1454489111232772683678306641953

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..60

Formula

a(n) = A000045(k) for the smallest k such that A001222(A000045(k)-1) >= n.

Example

a(4)= 2*3*3*3 + 1 = 55.
a(5) = 2*3*3*7*19 + 1 = 1597.

Maple

for n from 1 to 14 do for fib from 2 to 5000 do f := combinat[fibonacci](fib)-1 ; allf := op(2, ifactors(f)) ; pow := 0 : for i from 1 to nops(allf) do pow := pow + op(2, op(i, allf)) ; od : if pow >= n then printf("%d, ", f+1) ; break ; fi ; od : od ; # R. J. Mathar, Apr 13 2006

Prog

(PARI) { m=3; for(n=1, 30, while(bigomega(fibonacci(m)-1)<n, m++); print1(fibonacci(m), ", "); ) } \\ Max Alekseyev, Apr 22 2010

Crossrefs

Subset of A000045.

Cf. A000071, A001222, A081952.

Sequence in context: A264812 A276827 A034375 * A181848 A243161 A153207

Adjacent sequences: A081950 A081951 A081952 * A081954 A081955 A081956

Keyword

nonn

Author

Amarnath Murthy, Apr 02 2003

Extensions

More terms from R. J. Mathar, Apr 13 2006

Corrected and extended by Max Alekseyev, Apr 22 2010

Status

approved