Logo

Greetings from The On-Line Encyclopedia of Integer Sequences!

Hints

Search: id:A028871
Displaying 1-1 of 1 results found. page 1
     Format: long | short | internal | text      Sort: relevance | references | number      Highlight: on | off
A028871 Primes of form n^2 - 2. +0
24
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

MATHEMATICA

lst={}; Do[s=n^2; If[PrimeQ[p=s-2], AppendTo[lst, p]], {n, 6!}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Sep 26 2008]

CROSSREFS

Cf. A028870.

Sequence in context: A049552 A049572 A094786 this_sequence A053705 A049001 A049002

Adjacent sequences: A028868 A028869 A028870 this_sequence A028872 A028873 A028874

KEYWORD

nonn

AUTHOR

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

page 1

Search completed in 0.002 seconds

Lookup | Welcome | Find friends | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
More pages | Superseeker | Maintained by N. J. A. Sloane (njas@research.att.com)

Last modified November 25 20:09 EST 2009. Contains 167514 sequences.


AT&T Labs Research