A190801 Least semiprime whose prime factors differ by n!.

6, 15, 55, 145, 889, 5089, 55561, 927889, 6169249, 39916921, 678585889, 13891047241, 417210398089, 1656387533161, 56229997825849, 481224167424529, 11026310270976961, 236887827111937369, 10826413936386055921

Offset

1,1

Comments

Appears to be the same as A037152(n) * A037153(n).

Links

Table of n, a(n) for n=1..19.

Example

a(5) = 889 because 889 = 7 * 127 , and 127 - 7 = 120 = 5!

Mathematica

f[n_] := Block[{p=2}, While[! PrimeQ[p+n!], p=NextPrime[p]]; p*(p+n!)]; Table[f[n], {n, 60}]

Crossrefs

Sequence in context: A262912 A119132 A073065 * A093042 A373569 A270624

Adjacent sequences: A190798 A190799 A190800 * A190802 A190803 A190804

Keyword

nonn

Author

Michel Lagneau, May 20 2011

Status

approved