A246817 Possible number of trailing zeros in hyperfactorials (A002109).

0, 5, 15, 30, 50, 100, 130, 165, 205, 250, 350, 405, 465, 530, 600, 750, 830, 915, 1005, 1100, 1300, 1405, 1515, 1630, 1750, 2125, 2255, 2390, 2530, 2675, 2975, 3130, 3290, 3455, 3625, 3975, 4155, 4340, 4530, 4725, 5125, 5330, 5540, 5755, 5975, 6425, 6655

Offset: 1

Author

Chai Wah Wu, Sep 03 2014

Keywords

• nonn
• base

Comments

The number of trailing zeros in A002109 increases every 5 terms since the exponent of the factor 5 increases every 5 terms and the exponent of the factor 2 increases every 2 terms.

Links

• Chai Wah Wu, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A002109, A191610, A246839.

Programs

Python

from sympy import multiplicity
A246817, p5 = [0], 0
for n in range(5,5*10**3,5):
    p5 += multiplicity(5,n)*n
    A246817.append(p5) # Chai Wah Wu, Sep 05 2014