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A028871 Primes of form n^2 - 2. +0
3
2, 7, 23, 47, 79, 167, 223, 359, 439, 727, 839, 1087, 1223, 1367, 1847, 2207, 2399, 3023, 3719, 3967, 4759, 5039, 5623, 5927, 7919, 8647, 10607, 11447, 13687, 14159, 14639, 16127, 17159, 18223, 19319, 21023, 24023, 25919, 28559, 29927 (list; graph; listen)
OFFSET

1,1

COMMENT

Except for the initial term, primes equal to the product of two consecutive even numbers minus 1. - Giovanni Teofilatto (g.teofilatto(AT)tiscalinet.it), Sep 24 2004

REFERENCES

D. Shanks, Solved and Unsolved Problems in Number Theory, 2nd. ed., Chelsea, 1978, p. 31.

LINKS

P. De Geest, Palindromic Quasipronics of the form n(n+x)

Eric Weisstein's World of Mathematics, Near-Square Prime

EXAMPLE

a(3) = 23, 6^2 - 2*6 - 1 = 23

CROSSREFS

Cf. A028870.

Adjacent sequences: A028868 A028869 A028870 this_sequence A028872 A028873 A028874

Sequence in context: A049552 A049572 A094786 this_sequence A053705 A049001 A049002

KEYWORD

nonn

AUTHOR

Patrick De Geest (pdg(AT)worldofnumbers.com)

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Last modified May 17 13:36 EDT 2008. Contains 139908 sequences.


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