A090257 a(1) = 1, then least square such that every partial concatenation is a prime.

1, 1, 81, 729, 441, 729, 81, 1521, 59049, 1521, 9, 13689, 1089, 159201, 62001, 363609, 4761, 1521, 8649, 1147041, 110889, 29241, 233289, 370881, 558009, 7569, 710649, 59049, 184041, 301401, 56169, 77841, 71289, 233289, 81, 91809, 1535121, 9018009

Offset

0,3

Comments

a(n) == 0 (mod 9) for n>1. Conjecture: Sequence is infinite.

Links

Table of n, a(n) for n=0..37.

Example

11,1181,1181729 etc. are primes.

Crossrefs

Sequence in context: A232026 A133549 A235946 * A295233 A271829 A066431

Adjacent sequences: A090254 A090255 A090256 * A090258 A090259 A090260

Keyword

base,nonn

Author

Amarnath Murthy, Nov 27 2003

Extensions

More terms from David Wasserman, Oct 21 2005

Status

approved