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 A185351 Sums of distinct perfect numbers. 3
 0, 6, 28, 34, 496, 502, 524, 530, 8128, 8134, 8156, 8162, 8624, 8630, 8652, 8658, 33550336, 33550342, 33550364, 33550370, 33550832, 33550838, 33550860, 33550866, 33558464, 33558470, 33558492, 33558498, 33558960, 33558966, 33558988, 33558994, 8589869056 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS The first 131072 terms of this sequence are even. Conjecturally, all terms are even. Numbers in the range of the sum of perfect divisors function (A187794). - Timothy L. Tiffin, Jul 13 2016 LINKS Charles R Greathouse IV, Table of n, a(n) for n = 1..10000 EXAMPLE 502 = 496 + 6, where 496 and 6 are perfect. MATHEMATICA With[{perf = Select[Range[10000], DivisorSigma[1, #] == 2# &]}, Rest[Union[Total/@Subsets[perf]]]] (* Harvey P. Dale, Feb 07 2012 *) PROG (PARI) vecsum(v)=sum(i=1, #v, v[i]); v=apply(n->binomial(n+1, 2), select(k->ispseudoprime(k), vector(15, n, 2^prime(n)-1))); u=List(); for(i=0, 2^#v-1, listput(u, vecsum(vecextract(v, i)))); vecsort(Vec(u)) \\ Charles R Greathouse IV, Feb 09 2012 CROSSREFS Cf. A083865, A204879, A187794. Sequence in context: A145551 A259917 A083865 * A272971 A117948 A252234 Adjacent sequences:  A185348 A185349 A185350 * A185352 A185353 A185354 KEYWORD nonn AUTHOR Charles R Greathouse IV, Feb 09 2012 STATUS approved

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Last modified August 21 18:58 EDT 2019. Contains 326168 sequences. (Running on oeis4.)