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A070844 a(n) = smallest n-digit number with exactly n divisors, or 0 if no such number exists. 6
1, 11, 121, 1003, 14641, 100017, 1771561, 10000005, 100020001, 1000000016, 25937424601, 100000000004, 3138428376721, 10000000001344, 100000720001296, 1000000000000006, 45949729863572161, 100000000000000404 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

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

FORMULA

If n is a prime < 29 then a(n) = 11^(n-1). - Chandler

If n is a prime >= 29 then a(n) = 0. - Vladeta Jovovic, Aug 20 2002

MATHEMATICA

For[n=1, n<10, n++, k := 10^(n-1); While[Not[Length[Divisors[k]] == n], k++ ]; Print[k]] (Steinerberger)

CROSSREFS

Cf. A070845.

Sequence in context: A068179 A218262 A006940 * A164327 A080445 A033867

Adjacent sequences:  A070841 A070842 A070843 * A070845 A070846 A070847

KEYWORD

base,nonn

AUTHOR

Amarnath Murthy, May 12 2002

EXTENSIONS

a(6)-a(18) from Vladeta Jovovic, Aug 20 2002

a(6) confirmed by Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Apr 08 2003

a(7)-a(10) confirmed by Stefan Steinerberger, Feb 06 2006

a(15) corrected, and a(11)-a(14), a(16)-a(18) confirmed by Ray Chandler, Feb 10 2009

Edited by N. J. A. Sloane, Feb 14 2009 at the suggestion of Ray Chandler.

STATUS

approved

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Last modified March 28 21:25 EDT 2017. Contains 284246 sequences.