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A123723 Values of n for which A000224(n)=Ceiling[(n+1)/4], where A000224(n) is the number of squares mod n. 2
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified October 29 18:30 EDT 2020. Contains 338067 sequences. (Running on oeis4.)