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A057812 pi(n) is odd. 3
2, 5, 6, 11, 12, 17, 18, 23, 24, 25, 26, 27, 28, 31, 32, 33, 34, 35, 36, 41, 42, 47, 48, 49, 50, 51, 52, 59, 60, 67, 68, 69, 70, 73, 74, 75, 76, 77, 78, 83, 84, 85, 86, 87, 88, 97, 98, 99, 100, 103, 104, 105, 106, 109, 110, 111, 112, 127, 128, 129 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

Ping Ngai Chung and Shiyu Li, On the residue classes of π(n) modulo t, INTEGERS: Electronic Journal of Combinatorial Number Theory 13 (2013), A79.

FORMULA

Chang & Li show that a(n) < 64n + o(1), and a(n) < 8n + o(1) under the Hardy-Littlewood prime tuples conjecture. - Charles R Greathouse IV, Dec 19 2014

PROG

(PARI) is(n)=primepi(n)%2 \\ Charles R Greathouse IV, Dec 19 2014

CROSSREFS

Cf. A000720, A057811.

Sequence in context: A269966 A026344 A284488 * A140144 A030130 A164874

Adjacent sequences:  A057809 A057810 A057811 * A057813 A057814 A057815

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Nov 07 2000

STATUS

approved

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Last modified February 17 23:47 EST 2018. Contains 299297 sequences. (Running on oeis4.)