A075593 a(1) = 1, a(2n) = prime, a(2n+1) = composite and sum of two successive terms is alternately composite or prime.

1, 3, 4, 2, 9, 5, 6, 19, 10, 11, 8, 7, 12, 13, 16, 17, 14, 31, 22, 23, 18, 37, 24, 41, 20, 29, 30, 47, 26, 43, 28, 53, 36, 59, 38, 61, 40, 71, 32, 67, 34, 83, 44, 73, 54, 79, 48, 97, 42, 101, 50, 103, 46, 89, 60, 109, 58, 107, 56, 113, 66, 137, 62, 127, 52, 131, 68, 139, 72

Offset: 1

Author

Amarnath Murthy, Sep 27 2002

Keywords

• nonn

Comments

This is not a permutation of the positive integers; odd composites > 9 will not appear in the sequence. - Klaus Brockhaus, Feb 06 2006

Crossrefs

Cf. A075594, A103824, A103825.

Extensions

Extended by Ray Chandler Feb 16 2005