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A364858
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a(n) = Sum_{d|n, d < n, d in S} d, where S is the set defined in A118372.
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3
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0, 1, 1, 3, 1, 6, 1, 7, 4, 8, 1, 16, 1, 10, 9, 15, 1, 21, 1, 22, 11, 14, 1, 24, 6, 16, 13, 28, 1, 42, 1, 31, 15, 20, 13, 25, 1, 22, 17, 30, 1, 54, 1, 40, 33, 26, 1, 64, 8, 43, 21, 46, 1, 48, 17, 64, 23, 32, 1, 46, 1, 34, 41, 63, 19, 78, 1, 58, 27, 74, 1, 93, 1
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OFFSET
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1,4
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COMMENTS
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First differs from A294888 at n = 48.
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LINKS
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FORMULA
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a(n) <= n if and only if n is in the set S.
a(n) = n if and only if n is S-perfect (A118372).
a(n) > n if and only if n is S-abundant (A181487).
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MATHEMATICA
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seq[nmax_] := Module[{s = {1}, a = {0}, sum}, Do[sum = Total[Select[Divisors[n], MemberQ[s, #] &]]; If[sum <= n, AppendTo[s, n]]; AppendTo[a, sum], {n, 2, nmax}]; a]; seq[100]
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PROG
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(PARI) lista(nmax) = {my(c = 0, s); print1(0, ", "); for(n=2, nmax, s = sumdiv(n, d, !bittest(c, d)*d) - n; if(s > n, c+=1<<n); print1(s, ", ")); } \\ after M. F. Hasler at A181487
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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