

A182679


a(n) = the smallest ndigit number with exactly 10 divisors, a(n) = 0 if no such number exists.


2



0, 48, 112, 1053, 10096, 100112, 1000016, 10000017, 100000144, 1000000016, 10000000071, 100000000336, 1000000000304, 10000000000624, 100000000000528, 1000000000000016, 10000000000000503
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OFFSET

1,2


COMMENTS

a(n) = the smallest ndigit number of the form p^9 or p^4*q^1 (p, q = distinct primes), a(n) = 0 if no such number exists.


LINKS

Table of n, a(n) for n=1..17.


FORMULA

A000005(a(n)) = 10.


MATHEMATICA

Table[k=10^(n1); While[k<10^n && DivisorSigma[0, k] != 10, k++]; If[k==10^n, k=0]; k, {n, 10}]


PROG

(Sage) A182679 = lambda n: next((x for x in IntegerRange(10**(n1), 10**n) if number_of_divisors(x) == 10), 0)
# D. S. McNeil, Nov 28 2010


CROSSREFS

See A182680(n)  the largest ndigit number with exactly 10 divisors.
Sequence in context: A191837 A044235 A044616 * A260759 A211726 A232938
Adjacent sequences: A182676 A182677 A182678 * A182680 A182681 A182682


KEYWORD

nonn,base


AUTHOR

Jaroslav Krizek, Nov 27 2010


STATUS

approved



