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A190662 Least semiprime having prime factors that differ by 2*n!. 1
15, 21, 85, 265, 2761, 10129, 111001, 887161, 21047881, 210471241, 1037836969, 68018232241, 361167207241, 3312775065961, 49691625984361, 1548286451713369, 16361621692416529, 294509190463488529 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..18.

EXAMPLE

a(5) = 2761 because 2761 = 11 * 251 , and 251 - 11 = 240 = 2*120 = 2*5!

MATHEMATICA

f[n_] := Block[{p=3}, While[! PrimeQ[p+2*n!], p=NextPrime[p]]; p (p + 2*n!)]; Table[f[n], {n, 60}]

CROSSREFS

Cf. A190663.

Sequence in context: A063176 A083372 A119101 * A274084 A219918 A084931

Adjacent sequences:  A190659 A190660 A190661 * A190663 A190664 A190665

KEYWORD

nonn

AUTHOR

Michel Lagneau, May 16 2011

STATUS

approved

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Last modified October 23 14:54 EDT 2019. Contains 328345 sequences. (Running on oeis4.)