A139546 Numbers of form x^2+5y^2 (x>=0,y>=0) with repetition.

0, 1, 4, 5, 6, 9, 9, 14, 16, 20, 21, 21, 24, 25, 29, 30, 36, 36, 41, 45, 45, 46, 49, 49, 54, 54, 56, 61, 64, 69, 69, 70, 80, 81, 81, 81, 84, 84, 86, 89, 94, 96, 100, 101, 105, 105, 109, 116, 120, 121, 125, 126, 126, 126, 129, 129, 134, 141, 141, 144, 144, 145, 149, 150

Offset

1,3

Comments

Primes in the sequence occur only once.

References

David A. Cox, "Primes of the Form x^2 + n y^2", Wiley, 1989.

Links

Table of n, a(n) for n=1..64.

Example

0 = 0^2+5*0^2,
9 = 2^2+5*1^2 = 3^2+5*0^2,
81 = 1^2+5*4^2 = 6^2+5*3^2 = 9^2+5*0^2,
441: {x,y}={6,9},{11,8},{14,7},{19,4},{21,0}.

Crossrefs

Cf. A033205.

Sequence in context: A195355 A049466 A196551 * A369352 A308886 A029776

Adjacent sequences: A139543 A139544 A139545 * A139547 A139548 A139549

Keyword

nonn

Author

Zak Seidov, Apr 26 2008

Status

approved