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A192992 Odd n > 1 such that n+1 is a semiprime times a power of two. 1
7, 11, 15, 17, 19, 23, 27, 29, 31, 35, 39, 41, 43, 47, 49, 51, 55, 59, 63, 65, 67, 69, 71, 75, 77, 79, 83, 87, 91, 95, 97, 99, 101, 103, 109, 111, 113, 115, 119, 123, 127, 129, 131, 135, 137, 139, 143, 147, 151, 153, 155, 159, 163, 167, 169, 171, 173, 175 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Odd n (A005408(i>0; 2*j+1 for j>0) such that n+1 is a semiprime times a power of two. Odd n such that n+1 is a A001358(i) times a power of two. Odd n such that n+1 is in A192991. This is to thin numbers A192868 as semiprimes A001358 are to primes A000040.

LINKS

Table of n, a(n) for n=1..58.

FORMULA

a(n) = A192991(n) - 1.

EXAMPLE

239 is in the sequence because 239+1 = 240 = 6th semiprime * 2^4 = 3 * 5 * 16.

CROSSREFS

Cf. A005408, A001358, A192868, A192990, A192991.

Sequence in context: A053217 A144931 A166257 * A335652 A176852 A248630

Adjacent sequences:  A192989 A192990 A192991 * A192993 A192994 A192995

KEYWORD

nonn,easy

AUTHOR

Jonathan Vos Post, Jul 13 2011

STATUS

approved

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Last modified October 20 10:43 EDT 2021. Contains 348100 sequences. (Running on oeis4.)