A241495 Least number k not divisible by 10 such that k^n contains n zeros.

101, 101, 101, 101, 101, 351, 1244, 194, 4648, 951, 4357, 3757, 2169, 2392, 7399, 7501, 9723, 8683, 13867, 6152, 15204, 18898, 40141, 54631, 29647, 35586, 46564, 67743, 84789, 119421, 43055, 43642, 83055, 44411, 142553, 94501, 135852, 52299, 174062, 121201, 196205

Offset

1,1

Links

Table of n, a(n) for n=1..41.

Example

101 is not divisible by 10 and 101^1 (101), 101^2 (10201), 101^3 (1030301), 101^4 (104060401), and 101^5 (10510100501) all have 1, 2, 3, 4, and 5 zeros, respectively. So, a(1) = a(2) = a(3) = a(4) = a(5) = 101.

Prog

(Python)
def Cu(n):
..for k in range(10**10):
....if k% 10 != 0:
......if str(k**n).count("0") == n:
........return k
n = 1
while n < 100:
..print(Cu(n))
..n += 1
(PARI) a(n) = {k = 1; while (((k % 10) == 0) || (d = digits(k^n)) && (sum(i=1, #d, d[i] == 0) != n), k++); k; } \\ Michel Marcus, Apr 30 2014

Crossrefs

Cf. A233821.

Sequence in context: A282200 A266667 A368397 * A282980 A282950 A283087

Adjacent sequences: A241492 A241493 A241494 * A241496 A241497 A241498

Keyword

nonn,base

Author

Derek Orr, Apr 24 2014

Status

approved