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A176362 a(n) = sigma(n*2^(n-1)). 1
1, 7, 28, 63, 186, 508, 1016, 2047, 6643, 12282, 24564, 65532, 114674, 262136, 786408, 1048575, 2359278, 6815731, 10485740, 25165818, 67108832, 100663284, 201326568, 536870908, 1040187361, 1879048178, 5368709080, 8589934584 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..28.

FORMULA

Logarithmic derivative of A176361.

MATHEMATICA

Table[DivisorSigma[1, n 2^(n-1)], {n, 40}]  (* Harvey P. Dale, Mar 11 2011 *)

PROG

(PARI) a(n)=sigma(n*2^(n-1))

CROSSREFS

Cf. A176361, A176311, A000203 (sigma).

Sequence in context: A024844 A230285 A033582 * A008457 A138503 A223765

Adjacent sequences:  A176359 A176360 A176361 * A176363 A176364 A176365

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Apr 15 2010

STATUS

approved

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Last modified September 19 20:02 EDT 2020. Contains 337182 sequences. (Running on oeis4.)