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

Author

John W. Layman, Oct 12 2006

Keywords

• nonn

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.)

Crossrefs

Cf. A000224, A123722.