A352172 a(n) is the product of the cubes of the nonzero digits of n.

1, 8, 27, 64, 125, 216, 343, 512, 729, 1, 1, 8, 27, 64, 125, 216, 343, 512, 729, 8, 8, 64, 216, 512, 1000, 1728, 2744, 4096, 5832, 27, 27, 216, 729, 1728, 3375, 5832, 9261, 13824, 19683, 64, 64, 512, 1728, 4096, 8000, 13824, 21952, 32768, 46656, 125, 125, 1000, 3375, 8000, 15625

Offset: 1

Author

Michel Marcus, Mar 07 2022

Keywords

• nonn
• base

Links

• Michel Marcus, Table of n, a(n) for n = 1..10000

Crossrefs

Used in A351876.

Cf. A051801.

Programs

Mathematica

a[n_] := (Times @@ Select[IntegerDigits[n], # > 1 &])^3; Array[a, 55] (* Amiram Eldar, Mar 07 2022 *)

PARI

a(n) = vecprod(apply(x->x^3, select(x->(x>1), digits(n))));

Python

from math import prod
def a(n): return prod(int(d)**3 for d in str(n) if d != '0')
print([a(n) for n in range(1, 56)]) # Michael S. Branicky, Mar 07 2022

Python

from math import prod
def A352172(n): return prod(map(lambda x:(0, 1, 8, 27, 64, 125, 216, 343, 512, 729)[int(x)],filter(lambda x:x>'1',str(n)))) # Chai Wah Wu, Sep 17 2024