A075340 a(1) = 1; a(2n) is the smallest prime == 1 mod (a(2n-1)) and a(2n+1) is the smallest composite number == 1 (mod a(2n)).

1, 2, 9, 19, 20, 41, 42, 43, 44, 89, 90, 181, 182, 547, 548, 1097, 1098, 7687, 7688, 15377, 15378, 30757, 30758, 276823, 276824, 553649, 553650, 2768251, 2768252, 8304757, 8304758, 99657097, 99657098, 199314197, 199314198, 3189027169

Offset

1,2

Links

Table of n, a(n) for n=1..36.

Crossrefs

Cf. A075341.

Sequence in context: A342619 A342471 A180852 * A031316 A335051 A173663

Adjacent sequences: A075337 A075338 A075339 * A075341 A075342 A075343

Keyword

nonn

Author

Amarnath Murthy, Sep 18 2002

Extensions

More terms from David Wasserman, Jan 16 2005

Status

approved