A105364 Rearrangement of positive integers according to parity of (prime(n)-1)/2 (see comments).

2, 1, 4, 6, 3, 5, 8, 10, 7, 12, 9, 11, 14, 16, 13, 18, 15, 20, 22, 17, 24, 26, 19, 21, 23, 28, 30, 25, 27, 32, 34, 29, 36, 31, 38, 33, 40, 42, 35, 44, 37, 46, 39, 41, 48, 50, 52, 54, 43, 45, 56, 47, 58, 49, 60, 51, 62, 53, 55, 64, 57, 66, 68, 59, 61, 70, 63, 72, 65, 67, 74, 76

Offset

1,1

Comments

If (prime(n+1)-1)/2 is even/odd then a(n) is the next odd/even number.

Links

Table of n, a(n) for n=1..72.

Mathematica

bb={}; od=-1; ev=0; Do[If[OddQ[(Prime[i]-1)/2], ev=ev+2; bb=Append[bb, ev], od=od+2; bb=Append[bb, od]], {i, 2, 200}]; bb

Crossrefs

Cf. A105363.

Sequence in context: A293387 A306015 A171087 * A180405 A171007 A209168

Adjacent sequences: A105361 A105362 A105363 * A105365 A105366 A105367

Keyword

nonn

Author

Zak Seidov, Apr 01 2005

Status

approved