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A079887 Values of y-x where p runs through the primes of form 4k+1 and p=x^2+y^2, 0<=x<=y. 5
1, 1, 3, 3, 5, 1, 5, 1, 5, 3, 5, 9, 7, 1, 7, 3, 5, 11, 1, 5, 13, 13, 5, 11, 15, 3, 5, 11, 15, 1, 3, 7, 13, 9, 11, 7, 13, 19, 17, 1, 5, 13, 17, 9, 17, 9, 11, 5, 7, 23, 15, 19, 1, 3, 21, 9, 19, 11, 25, 21, 7, 25, 17, 1, 13, 5, 15, 23, 11, 17, 5, 25, 23, 9, 3, 5, 19, 15, 27, 25, 13, 1, 19, 29, 27 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Also values of x where p runs through the primes of form 4k+1 and 2*p=x^2+y^2, 0<=x<y. - Colin Barker, Jul 07 2014

LINKS

Table of n, a(n) for n=1..85.

FORMULA

a(n) = A002330(n+1)-A002231(n+1). - R. J. Mathar, Jan 09 2017

MATHEMATICA

pp = Select[ Range[200] // Prime, Mod[#, 4] == 1 &]; f[p_] := y - x /. ToRules[ Reduce[0 <= x <= y && p == x^2 + y^2, {x, y}, Integers]]; A079887 = f /@ pp (* Jean-Fran├žois Alcover, Jan 15 2015 *)

CROSSREFS

Cf. A002330, A002331, A002313, A002144, A079886.

Sequence in context: A011399 A205853 A240594 * A131843 A205550 A209389

Adjacent sequences:  A079884 A079885 A079886 * A079888 A079889 A079890

KEYWORD

nonn

AUTHOR

Benoit Cloitre, Jan 13 2003

STATUS

approved

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Last modified January 27 10:39 EST 2022. Contains 350607 sequences. (Running on oeis4.)