A138970 - OEIS

A138970

Positions of the primes congruent to 1 mod 4 when all primes except 2 are listed in order.

2, 5, 6, 9, 11, 12, 15, 17, 20, 23, 24, 25, 28, 29, 32, 34, 36, 39, 41, 43, 44, 49, 50, 52, 54, 56, 58, 59, 61, 64, 65, 67, 69, 70, 73, 76, 77, 78, 79, 81, 83, 86, 87, 88, 96, 97, 99, 101, 103, 105, 107, 109, 111, 112, 115, 118, 120, 121, 122, 125, 126, 129, 133, 134, 135

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OFFSET

1,1

COMMENTS

Complement of A138971 (positions of primes congruent to 3 mod 4).

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

MATHEMATICA

Position[Table[If[Mod[p, 4]==1, 1, 0], {p, Prime[Range[2, 200]]}], 1]//Flatten (* Harvey P. Dale, Jun 22 2021 *)

CROSSREFS

Cf. A138971.

Sequence in context: A075724 A049408 A342733 * A168550 A355431 A244737

Adjacent sequences: A138967 A138968 A138969 * A138971 A138972 A138973

KEYWORD

nonn

AUTHOR

Clark Kimberling, Apr 05 2008

STATUS

approved