A217560 Terms as well as digits have alternating primality; this is the lexicographically earliest injective sequence with this property.

1, 2, 4, 3, 6, 5, 8, 7, 9, 29, 20, 31, 21, 59, 24, 71, 26, 79, 28, 263, 12, 13, 15, 17, 42, 43, 45, 47, 62, 67, 63, 83, 65, 97, 82, 131, 30, 283, 85, 139, 34, 293, 87, 151, 36, 307, 92, 179, 38, 313, 93, 421, 39, 317, 95, 431, 50, 347, 120, 367, 121, 383, 124, 397, 126, 503, 128, 547, 129, 563, 130, 587, 134, 593, 136, 743, 138, 787

Offset

1,2

Comments

Exactly every other term, and also every other digit (in concatenated terms) is prime.

Links

Carole Dubois, Table of n, a(n) for n = 1..5292

E. Angelini, Non-primes/primes: integers and digits alternate, SeqFan mailing list, Oct 06 2012

Carole Dubois, Graph with even ranges and odd ranges separated

Crossrefs

The sequence A217559 is a simplified variant.

See also A217555, A217556, where "primality" is replaced by "parity".

Sequence in context: A073846 A110458 A217559 * A114112 A113981 A234519

Adjacent sequences: A217557 A217558 A217559 * A217561 A217562 A217563

Keyword

nonn,base

Author

Eric Angelini and M. F. Hasler, Oct 06 2012

Extensions

Values from a(26)=43 on corrected by Jean-Marc Falcoz, Oct 10 2012

Status

approved