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A233821 Smallest zeroless number x such that x^n has exactly n zero digits. 1
245, 126, 245, 321, 351, 1244, 194, 4648, 951, 4357, 3757, 2169, 2392, 7399, 8379, 9723, 8683, 13867, 6152, 24887, 18898, 55825, 54631, 29647, 35586, 46564, 67743, 84789, 119421, 72296, 43642, 92233, 44411, 142553, 126693, 135852, 52299, 229626, 143951 (list; graph; refs; listen; history; text; internal format)
OFFSET
2,1
LINKS
EXAMPLE
951 has no zeros and 951^10 has ten zeros (605069371210073000039238122001). This is the least positive integer with this property.
MAPLE
N:= 30: # to get terms up to a(N)
for n from 2 to N do
for k from 1 do
if numboccur(0, convert(k, base, 10)) = 0 and
numboccur(0, convert(k^n, base, 10)) = n then
A[n]:= k;
break
fi
od
od:
seq(A[n], n=2..N); # Robert Israel, Aug 05 2014
PROG
(Python)
def GetNums(x):
..for n in range(10**6):
....if str(n).count("0") == 0:
......if str(n**x).count("0") == x:
........return n
x = 2
while x < 50:
..print(GetNums(x), end=', ')
..x += 1
(PARI) okxn(x, n) = {ok = 0; if (vecmin (digits(x)), dxn = digits(x^n); ok = (sum(i=1, #dxn, dxn[i] == 0) == n); ); ok; }
a(n) = {x=1; while (! okxn(x, n), x++); x; } \\ Michel Marcus, Dec 23 2013
CROSSREFS
Cf. A052382.
Sequence in context: A291587 A220090 A013684 * A216233 A157246 A186460
KEYWORD
nonn,base
AUTHOR
Derek Orr, Dec 16 2013
EXTENSIONS
More terms from Michel Marcus, Dec 23 2013
Definition edited by Robert Israel, Aug 05 2014
Definition simplified by Derek Orr, Mar 23 2015
STATUS
approved

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Last modified April 18 10:01 EDT 2024. Contains 371779 sequences. (Running on oeis4.)