cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A182679 a(n) = the smallest n-digit number with exactly 10 divisors, a(n) = 0 if no such number exists.

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%I A182679 #15 Feb 23 2014 13:58:06
%S A182679 0,48,112,1053,10096,100112,1000016,10000017,100000144,1000000016,
%T A182679 10000000071,100000000336,1000000000304,10000000000624,
%U A182679 100000000000528,1000000000000016,10000000000000503
%N A182679 a(n) = the smallest n-digit number with exactly 10 divisors, a(n) = 0 if no such number exists.
%C A182679 a(n) = the smallest n-digit number of the form p^9 or p^4*q^1 (p, q = distinct primes), a(n) = 0 if no such number exists.
%F A182679 A000005(a(n)) = 10.
%t A182679 Table[k=10^(n-1); While[k<10^n && DivisorSigma[0, k] != 10, k++]; If[k==10^n, k=0]; k, {n, 10}]
%o A182679 (Sage) A182679 = lambda n: next((x for x in IntegerRange(10**(n-1), 10**n) if number_of_divisors(x) == 10),0)
%o A182679 # _D. S. McNeil_, Nov 28 2010
%Y A182679 See A182680(n) - the largest n-digit number with exactly 10 divisors.
%K A182679 nonn,base
%O A182679 1,2
%A A182679 _Jaroslav Krizek_, Nov 27 2010