A091195 Number of numbers <= n having only one abundant divisor (A091191).

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10

Offset

1,18

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Eric Weisstein's World of Mathematics, Abundant Number.

Mathematica

f[n_] := Boole[Count[Divisors[n], _?(DivisorSigma[1, #] > 2 # &)] == 1]; Accumulate @ Array[f, 100] (* Amiram Eldar, Mar 21 2021 *)

Crossrefs

Partial sums of A294930.

Cf. A091191, A091194, A005101.

Sequence in context: A156878 A214454 A140474 * A280617 A072375 A340500

Adjacent sequences: A091192 A091193 A091194 * A091196 A091197 A091198

Keyword

nonn

Author

Reinhard Zumkeller, Dec 27 2003

Status

approved