STATUS
proposed
approved
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Revision History for A001157
(Bold, blue-underlined text is an addition; faded, red-underlined text is aShowing entries 1-10 | older changes
STATUS
editing
proposed
PROG
(Python)
from math import prod
from sympy import factorint
def a(n): return prod((p**(2*e+2)-1)//(p**2-1) for p, e in factorint(n).items())
print([a(n) for n in range(1, 51)]) # Michael S. Branicky, Feb 25 2024
STATUS
approved
editing
STATUS
editing
approved
CROSSREFS
Cf. A333972 (Dgf at s=4).
STATUS
approved
editing
FORMULA
a(n) = 1/J_2(n) * Sum_{d divides n} J_2(n*d), where J_2(n) is the Jordan totient function A007434(n) ?. - Peter Bala, Jan 26 2024
STATUS
editing
approved
FORMULA
a(n) = 1/J_2(n) * Sum_{d divides n} J_2(n*d), where J_2(n) is the Jordan totient function A007434(n) ?. - Peter Bala, Jan 26 2024
STATUS
approved
editing
STATUS
reviewed
approved
STATUS
proposed
reviewed
STATUS
editing
proposed