A086558 Smallest n-digit number beginning with n and having prime signature of n, or 0 if no such number exists.

1, 23, 307, 4489, 50021, 600007, 7000003, 80062991, 900660121, 1000000006, 11000000021, 120000000004, 1300000000021, 14000000000001, 150000000000017, 1604502443050081, 17000000000000009, 180000000000000027

Offset

1,2

Comments

Conjecture: no term is zero.

Links

Table of n, a(n) for n=1..18.

Example

a(4) = 4489 = 67^2, 4= 2^2. a(12) = 120000000004= 2^2*30000000001, prime signature: p^2*q.

Crossrefs

Sequence in context: A022651 A267266 A077504 * A090927 A045530 A080188

Adjacent sequences: A086555 A086556 A086557 * A086559 A086560 A086561

Keyword

base,nonn

Author

Amarnath Murthy, Aug 30 2003

Extensions

Corrected and extended by Sascha Kurz, Sep 22 2003

Status

approved