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A192868 Thin numbers: odd n > 1 such that n+1 is a prime times a power of two. 2
3, 5, 7, 9, 11, 13, 15, 19, 21, 23, 25, 27, 31, 33, 37, 39, 43, 45, 47, 51, 55, 57, 61, 63, 67, 73, 75, 79, 81, 85, 87, 91, 93, 95, 103, 105, 111, 115, 117, 121, 123, 127, 133, 135, 141, 145, 147, 151, 157, 159, 163, 165, 171, 175, 177, 183, 187, 191, 193 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..59.

Kevin Broughan and Zhou Qizhi, Flat primes and thin primes, Bulletin of the Australian Mathematical Society 82:2 (2010), pp. 282-292.

FORMULA

a(n) ~ n log n.

PROG

(PARI) is(n)=n%2&&(isprime((n+1)>>valuation(n+1, 2)) || n+1 == 1<<valuation(n+1, 2))&&n>1

CROSSREFS

Cf. A192869.

Sequence in context: A005842 A204458 A192861 * A283553 A081110 A143449

Adjacent sequences:  A192865 A192866 A192867 * A192869 A192870 A192871

KEYWORD

nonn

AUTHOR

Charles R Greathouse IV, Jul 11 2011

STATUS

approved

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Last modified November 16 19:17 EST 2019. Contains 329201 sequences. (Running on oeis4.)