A175082 Possible values for sum of perfect divisors of n.

1, 2, 3, 5, 6, 7, 10, 11, 12, 13, 14, 15, 17, 18, 19, 20, 21, 22, 23, 24, 26, 28, 29, 30, 31, 33, 34, 35, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75

Offset

1,2

Comments

Perfect divisor of n is divisor d such that d^k = n for some k >= 1. See A175067 (sum of perfect divisors of n) and A175081 (values taken by the sum of perfect divisors of n (A175067) sorted into ascending order).

Complement of A001597(n+1) for n >= 1 (perfect powers >= 4). a(n) = A007916(n-1) for n >= 2. - Jaroslav Krizek, Jan 30 2010

Links

Michael De Vlieger, Table of n, a(n) for n = 1..10000

Mathematica

nn = 100; s = Union@ Flatten@ Table[k^m, {m, 2, Log2[nn]}, {k, 2, Surd[nn, m] } ]; Complement[Range[s[[-1]] ], s] (* Michael De Vlieger, Apr 01 2026 *)

Crossrefs

Cf. A001597, A007916.

Sequence in context: A094784 A085971 A387421 * A007916 A052485 A341646

Adjacent sequences: A175079 A175080 A175081 * A175083 A175084 A175085

Keyword

nonn,easy

Author

Jaroslav Krizek, Jan 24 2010

Status

approved