login
A091195
Number of numbers <= n having only one abundant divisor (A091191).
2
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
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.
Sequence in context: A156878 A214454 A140474 * A280617 A072375 A340500
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Dec 27 2003
STATUS
approved