A182749 a(n) = the smallest multiple of n with n digits and exactly n divisors. a(n) = 0 if no such number exists.

1, 0, 0, 0, 0, 0, 0, 10000024, 100580841, 0, 25937424601, 100000000068, 0, 0, 0, 1000000000001152, 0, 100000000000000404, 0, 10000000000000000880, 0, 0, 0, 100000000000000000001184, 1000060001350013500050625, 0, 100000000015460000000597529, 1000000000000000000000022464

Offset: 1

Author

Jaroslav Krizek, Nov 27 2010

Keywords

• nonn
• base

Comments

Conjecture: a(n) > 0 for all nonsquarefree n except for n = 4. - Jon E. Schoenfield, Jun 01 2024

Links

• Jon E. Schoenfield, Table of n, a(n) for n = 1..100

Crossrefs

Cf. A000005, A073904, A182750.

Formula

A000005(a(n)) = n for a(n) > 0.

a(n) <= A182750(n).

Extensions

a(16), a(18), a(20) corrected by Jon E. Schoenfield, May 26 2024

a(21)-a(23) (implied by A182750) from Pontus von Brömssen, May 26 2024

a(24)-a(25) from Michael S. Branicky, May 26 2024

a(26)-a(28) from Jon E. Schoenfield, May 26 2024