A124512 a(n) = A124508(A124508(A124508(n))).

1, 144, 144, 288, 144, 576, 144, 576, 288, 576, 144, 1152, 144, 576, 576, 1152, 144, 1152, 144, 1152, 576, 576, 144, 2304, 288, 576, 576, 1152, 144, 2304, 144, 2304, 576, 576, 576, 2304, 144, 576, 576, 2304, 144, 2304, 144, 1152, 1152, 576, 144, 4608, 288

Offset: 1

Author

Reinhard Zumkeller, Nov 04 2006

Keywords

• nonn
• easy

Links

• Antti Karttunen, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A001221, A001222, A003586, A124508, A124511.

Programs

Mathematica

a[n_] := 9 * 2^(PrimeNu[n] + PrimeOmega[n] + 2); a[1] = 1; Array[a, 100] (* Amiram Eldar, Jul 11 2023 *)

PARI

A124508(n) = (2^bigomega(n) * 3^omega(n));
A124512(n) = A124508(A124508(A124508(n))); \\ Antti Karttunen, Jul 07 2017

PARI

a(n) = my(f = factor(n)); if(n == 1, 1, 9 * 2^(omega(f) + bigomega(f) + 2)); \\ Amiram Eldar, Jul 11 2023

Formula

a(n) = A124508(A124511(n)) = A124511(A124508(n)).

a(n) = 4*A124511(n) for n > 1.

For primes p, q with p<>q: a(p) = 144; a(p*q) = 576; a(p^k) = 9*2^(k+3), k > 0.

a(n) = 9 * 2^(omega(n) + Omgea(n) + 2) = 9 * 2^(A001221(n) + A001222(n) + 2), for n >= 2. - Amiram Eldar, Jul 11 2023