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A138828 Sum of digits of n-th even perfect number. 1
6, 10, 19, 19, 28, 64, 55, 73, 190, 235, 289, 352, 1405, 1711, 3520, 5833, 5968, 8821, 11548, 11791, 26317, 27298, 30232, 53740, 58960, 62956, 120898, 233722, 299314, 356860, 585478, 2048248, 2329372, 3405232, 3789352, 8056495, 8186041, 18894079, 36485416, 56880973, 65115946, 70334902, 82384129 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Ivan Panchenko, Table of n, a(n) for n = 1..47

Omar E. Pol, Determinacion geometrica de los numeros primos y perfectos.

FORMULA

a(n) = A007953(A000396(n)). - R. J. Mathar, May 22 2008 [This assumes that all perfect numbers are even. - Ivan Panchenko, Aug 16 2018]

MATHEMATICA

a[n_] := Block[{e, p, mpe = MersennePrimeExponent@n}, Plus @@ IntegerDigits[(2^mpe - 1) 2^(mpe - 1)]]; Array[a, 44] (* Robert G. Wilson v, Aug 06 2018 *)

Total[IntegerDigits[#]]&/@Table[PerfectNumber[n], {n, 43}] (* Requires Mathematica version 10 or later *) (* The program may take a long time to run *) (* Harvey P. Dale, Feb 07 2019 *)

CROSSREFS

Cf. A000396, A007605, A066538, A138127.

Sequence in context: A134351 A307458 A287273 * A109312 A257858 A095985

Adjacent sequences:  A138825 A138826 A138827 * A138829 A138830 A138831

KEYWORD

base,nonn

AUTHOR

Omar E. Pol, Apr 01 2008

EXTENSIONS

More terms from R. J. Mathar, May 22 2008

a(15)-a(38) from Donovan Johnson, Nov 09 2010

Definition changed (inserting the word "even") and a(39)-a(43) added by Ivan Panchenko, Aug 06 2018

STATUS

approved

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Last modified July 23 04:27 EDT 2019. Contains 325234 sequences. (Running on oeis4.)