

A091417


Integers n which are not the difference of 2 integers A and B where A is less than or equal to n such that AB+1 and AB1 are both primes. In other words, the product A*B cannot be the middle integer of a twin prime pair.


1



8, 9, 10, 15, 18, 20, 30, 40, 51, 58, 60, 65, 75, 96, 100, 110, 120, 170, 195, 240, 250, 260, 315, 330, 345, 390, 540, 630, 750, 780, 910, 1020, 1720, 1890
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OFFSET

1,1


COMMENTS

Sequence may be finite. Next term after 1890 if it exists must be greater than 867750.


LINKS



EXAMPLE

8 is a member: 8 is the difference between these pairs of integers: (91) (102) (113) (124) (135) (146) (157) (168). Their products (9*1) (10*2), etc. plus and minus 1 are not primes and therefore the products cannot be the middle integers of twin prime sets.


CROSSREFS



KEYWORD

nonn,fini


AUTHOR

William F. Sindelar (w_sindelar(AT)juno.com), Jan 05 2004


STATUS

approved



