A083192 a(1) = 1, then the rearrangement of composite numbers such that the concatenation of n terms from the n-th term is a prime. (Concatenation of n-th term to (2n-1)th term is a prime number).

1, 4, 21, 6, 49, 8, 77, 9, 39, 10, 81, 12, 221, 14, 63, 15, 203, 16, 143, 18, 511, 20, 217, 22, 279, 24, 299, 25, 319, 26, 33, 27, 147, 28, 943, 30, 121, 32, 87, 34, 333, 35, 781, 36, 249, 38, 679, 40, 99, 42, 117, 44, 1463, 45, 697, 46, 187, 48, 207, 50, 219, 51, 639, 52

Offset

1,2

Links

Table of n, a(n) for n=1..64.

Example

421, 21649, etc. are primes.

Crossrefs

Cf. A083193.

Sequence in context: A244955 A272969 A327085 * A225540 A128452 A333433

Adjacent sequences: A083189 A083190 A083191 * A083193 A083194 A083195

Keyword

base,nonn

Author

Amarnath Murthy, Apr 27 2003

Extensions

Corrected a(11)=81 and extended by Ray Chandler, Jan 04 2009

Status

approved