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A081952
Smallest Fibonacci number which is one more than the product of n distinct numbers > 1.
3
3, 13, 55, 1597, 17711, 1346269, 165580141, 2971215073, 7778742049, 308061521170129, 308061521170129, 135301852344706746049, 3311648143516982017180081, 1983924214061919432247806074196061
OFFSET
1,1
LINKS
FORMULA
a(n) = A000045(A119249(n)). - R. J. Mathar, Feb 06 2010
EXAMPLE
a(3) = 2*3*9 + 1 = 55;
a(4) = 3*4*7*19 + 1 = 1597;
a(5) = 2*5*7*11*23 + 1 = 17711;
a(6) = 3*4*7*11*31*47 + 1 = 1346269;
a(7) = 3*4*5*11*29*41*211 + 1 = 165580141;
a(8) = 2*3*6*7*8*23*139*461 + 1 = 2971215073.
MATHEMATICA
f[n_, m_, 0] := n == 1; f[n_, m_, d_] := (b = False; l = Select[Divisors[n], #>=m&]; For[i = 1, i <= Length[l], i++, k = l[[i]]; If[f[n / k, k + 1, d - 1], b = True; Break[]]]; b); Do[x = 3; While[ !f[Fibonacci[x] - 1, 2, y], x++ ]; Print[Fibonacci[x]], {y, 1, 50}] (* Ryan Propper, Jul 22 2006 *)
CROSSREFS
Subset of A000045.
Sequence in context: A151219 A006225 A100588 * A234645 A010920 A010903
KEYWORD
nonn
AUTHOR
Amarnath Murthy, Apr 02 2003
EXTENSIONS
More terms from R. J. Mathar, Apr 13 2006
More terms from Ryan Propper, Jul 22 2006
Edited by Jon E. Schoenfield, Nov 18 2018
STATUS
approved