A181581 Smallest k such that each of the five factorials (5k)!, (5k+1)!, (5k+2)!, (5k+3)! and (5k+4)! has exactly 10^n trailing 0's. Zero, if no such k exists.

1, 9, 81, 801, 8002, 80001, 800001, 8000002, 80000003, 800000003, 8000000003, 80000000003, 800000000002, 8000000000003, 80000000000004, 0, 0, 0, 800000000000000004, 8000000000000000003, 0, 800000000000000000005, 8000000000000000000006, 0

Offset: 0

Author

Lekraj Beedassy, Nov 02 2010

Keywords

• nonn

Comments

a(n) = A173558(n)/5 or 0.

Links

• Hiroaki Yamanouchi, Table of n, a(n) for n = 0..100
• Index to sequences related to factorial numbers.

Crossrefs

Cf. A027868, A173558.

Extensions

a(15)-a(17) corrected and a(18)-a(23) added by Hiroaki Yamanouchi, Oct 06 2014