login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A363895
Floor of the average of the distinct prime factors of n.
4
2, 3, 2, 5, 2, 7, 2, 3, 3, 11, 2, 13, 4, 4, 2, 17, 2, 19, 3, 5, 6, 23, 2, 5, 7, 3, 4, 29, 3, 31, 2, 7, 9, 6, 2, 37, 10, 8, 3, 41, 4, 43, 6, 4, 12, 47, 2, 7, 3, 10, 7, 53, 2, 8, 4, 11, 15, 59, 3, 61, 16, 5, 2, 9, 5, 67, 9, 13, 4, 71, 2, 73, 19, 4, 10, 9, 6, 79
OFFSET
2,1
FORMULA
a(p^n) = p, p prime, n >= 1.
a(n) = floor(A008472(n)/A001221(n)).
a(n) = floor(A323171(n)/A323172(n)).
MATHEMATICA
a[n_] := Floor[Mean[FactorInteger[n][[;; , 1]]]]; Array[a, 100, 2] (* Amiram Eldar, Jun 27 2023 *)
PROG
(Python)
from sympy import factorint
def a(n):
P = factorint(n).keys()
return int(sum(P)/len(P))
print([a(n) for n in range(2, 85)])
(PARI) a(n) = my(p = factor(n)[, 1]); vecsum(p)\#p; \\ Amiram Eldar, Jun 29 2023
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Darío Clavijo, Jun 26 2023
STATUS
approved