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A288443 a(n) = (2n + 1)*2^(2n + 1); numbers k such that v(k)*2^v(k) = k, where v(n) = A007814(n) is 2-adic valuation of n. 0
2, 24, 160, 896, 4608, 22528, 106496, 491520, 2228224, 9961472, 44040192, 192937984, 838860800, 3623878656, 15569256448, 66571993088, 283467841536, 1202590842880, 5085241278464, 21440476741632, 90159953477632, 378231999954944, 1583296743997440, 6614661952700416, 27584547717644288, 114841790497947648 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Table of n, a(n) for n=0..25.

FORMULA

a(n) = (2n + 1)*2^(2n + 1).

a(n) = A036289(2n + 1).

a(n) = A098713(n) + 1.

a(n) = 2*A058962(n). - Joerg Arndt, Jun 25 2017

From Amiram Eldar, Jul 03 2020: (Start)

Sum_{n>=0} 1/a(n) = arctanh(1/2) = log(3)/2 (A156057).

Sum_{n>=0} (-1)^n/a(n) = arctan(1/2) (A073000). (End)

PROG

(MAGMA) [(2*n+1)*2^(2*n+1): n in [0..25]];

(PARI) a(n) = (2*n+1)<<(2*n+1) \\ Charles R Greathouse IV, Jul 07 2017

CROSSREFS

Cf. A007814, A058962, A098713, A286683.

Odd bisection of A036289.

Cf. A073000, A156057.

Sequence in context: A189247 A234352 A241623 * A108476 A157053 A279853

Adjacent sequences:  A288440 A288441 A288442 * A288444 A288445 A288446

KEYWORD

nonn,easy

AUTHOR

Juri-Stepan Gerasimov, Jun 24 2017

STATUS

approved

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Last modified August 14 01:55 EDT 2020. Contains 336476 sequences. (Running on oeis4.)