A361708 Inverse Moebius transform of nonprimes.
1, 5, 7, 13, 10, 21, 13, 27, 22, 30, 19, 49, 22, 39, 40, 52, 27, 63, 29, 68, 51, 56, 35, 98, 46, 64, 61, 87, 43, 114, 46, 98, 73, 80, 72, 142, 53, 87, 83, 138, 58, 145, 61, 126, 118, 103, 66, 189, 81, 135, 103, 144, 75, 177, 104, 178, 113, 127, 82, 254, 85, 135, 152, 185, 119
Offset: 1
Links
- Paolo Xausa, Table of n, a(n) for n = 1..10000
- N. J. A. Sloane, Transforms
Programs
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Maple
Nonprime:= remove(isprime, [$1..1000]): N:= nops(Nonprime): seq(add(Nonprime[d],d=numtheory:-divisors(n)),n=1..N); # Robert Israel, Mar 23 2023
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Mathematica
With[{np = Select[Range[100],!PrimeQ[#] &]}, Table[DivisorSum[n, np[[#]] &], {n, Length[np]}]] (* Paolo Xausa, Aug 21 2025 *)
Formula
a(n) = Sum_{d|n} A018252(d).