The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A048785

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A048785

a(0) = 0; a(n) = tau(n^3), where tau = number of divisors (A000005).
(history; published version)

#67 by Alois P. Heinz at Tue May 10 13:57:26 EDT 2022

STATUS

proposed

approved

#66 by Karl-Heinz Hofmann at Tue May 10 13:53:32 EDT 2022

STATUS

editing

proposed

#65 by Karl-Heinz Hofmann at Tue May 10 13:53:27 EDT 2022

PROG

(Python) from sympy import divisor_count

def A048785(n): return divisor_count(n**3) # Karl-Heinz Hofmann, May 10 2022

CROSSREFS

Cf. A000005, A001221, A048691, A074816, A144943, A353551.

STATUS

approved

editing

#64 by Alois P. Heinz at Tue May 10 13:30:09 EDT 2022

STATUS

proposed

approved

#63 by Chai Wah Wu at Tue May 10 13:28:05 EDT 2022

STATUS

editing

proposed

#62 by Chai Wah Wu at Tue May 10 13:27:58 EDT 2022

PROG

(Python)

from math import prod

from sympy import factorint

def A048785(n): return 0 if n == 0 else prod(3*e+1 for e in factorint(n).values()) # Chai Wah Wu, May 10 2022

STATUS

approved

editing

#61 by Vaclav Kotesovec at Fri Aug 20 16:57:48 EDT 2021

STATUS

editing

approved

#60 by Vaclav Kotesovec at Fri Aug 20 13:02:40 EDT 2021

FORMULA

Dirichlet g.f.: zeta(s)^4 * Product_{primes p} (1 - 3/p^(2*s) + 2/p^(3*s)). - Vaclav Kotesovec, Aug 20 2021

PROG

print1("0, "); for(n=1, 100, print1(direuler(p=2, n, (1 - 3*X^2 + 2*X^3)/(1 - X)^4)[n], ", ")) \\ Vaclav Kotesovec, Aug 20 2021

STATUS

approved

editing

#59 by Joerg Arndt at Sun May 16 01:50:20 EDT 2021

STATUS

reviewed

approved

#58 by Wesley Ivan Hurt at Sun May 16 00:56:07 EDT 2021

STATUS

proposed

reviewed