A123723 Values of n for which A000224(n)=Ceiling[(n+1)/4], where A000224(n) is the number of squares mod n.

1, 4, 8, 12, 20, 28, 44, 45, 52, 63, 68, 76, 92, 116, 124, 126, 148, 164, 172, 175, 188, 212, 236, 244, 268, 284, 292, 316, 332, 350, 356, 388, 404, 412, 428, 436, 452, 508, 524, 548, 556, 596, 604, 628, 652, 668, 692, 716, 724, 764, 772, 788, 796, 844, 892

Offset

1,2

Comments

Conjecture. If n>4 and a(n) is a multiple of 4, then a(n)/4 is a prime. (This has been verified up to n = 2000.)

Links

Table of n, a(n) for n=1..55.

Crossrefs

Cf. A000224, A123722.

Sequence in context: A311663 A333572 A322958 * A279227 A261649 A298797

Adjacent sequences: A123720 A123721 A123722 * A123724 A123725 A123726

Keyword

nonn

Author

John W. Layman, Oct 12 2006

Status

approved