A190801 - OEIS

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

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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