A088062 a(1) = 2; thereafter a(n) = smallest number of copies of (the decimal expansion of) n that are needed to prefix A088061(n-1) with in order to get a prime (the prime being A088061(n)).

2, 1, 2, 3, 2, 1, 12, 634, 623

Offset

1,1

Links

Table of n, a(n) for n=1..9.

Example

a(4) = 3, A088061(3) = 33211 and A088061(4) = 44433211.

Prog

(PARI) x=0; n=-1; for(k=1, 9, z=n; while(1, n++; x=x+k*10^n; if(ispseudoprime(x), print(z=n-z); break))) \\ Dmitry Petukhov, Oct 15 2017

Crossrefs

Cf. A088061.

Sequence in context: A115116 A141662 A328383 * A248886 A123884 A178412

Adjacent sequences: A088059 A088060 A088061 * A088063 A088064 A088065

Keyword

base,more,nonn

Author

Amarnath Murthy, Sep 21 2003

Extensions

a(8) from David Wasserman, Jul 01 2005

a(9) from Dmitry Petukhov, Oct 15 2017

Status

approved