A159482 Greatest odd prime q < 2*n such that p < q and p prime and p = 2*n - q or 0 if no such prime exists.

0, 0, 0, 5, 7, 7, 11, 13, 13, 17, 19, 19, 23, 23, 23, 29, 31, 31, 31, 37, 37, 41, 43, 43, 47, 47, 47, 53, 53, 53, 59, 61, 61, 61, 67, 67, 71, 73, 73, 73, 79, 79, 83, 83, 83, 89, 89, 89, 79, 97, 97, 101, 103, 103, 107, 109, 109, 113, 113, 113, 109, 113, 113, 109, 127, 127

Offset

1,4

Comments

q + p = 2*n and p*q = ((q+p)/2)^2 - ((q-p)/2)^2 = n^2 - ((q-p)/2)^2.

Essentially the same as A020482. - R. J. Mathar, Oct 24 2009

Links

Pierre CAMI, Table of n, a(n) for n = 1..55000

Crossrefs

Sequence in context: A078496 A114521 A258653 * A231935 A216835 A033932

Adjacent sequences: A159479 A159480 A159481 * A159483 A159484 A159485

Keyword

nonn

Author

Pierre CAMI, Apr 14 2009

Status

approved