A135762 Start with sequence of positive integers, then swap a(i) and a(i-1) if a(i) is an odd prime.

1, 3, 2, 5, 4, 7, 6, 8, 9, 11, 10, 13, 12, 14, 15, 17, 16, 19, 18, 20, 21, 23, 22, 24, 25, 26, 27, 29, 28, 31, 30, 32, 33, 34, 35, 37, 36, 38, 39, 41, 40, 43, 42, 44, 45, 47, 46, 48, 49, 50, 51, 53, 52, 54, 55, 56, 57, 59, 58, 61, 60, 62, 63, 64, 65, 67, 66, 68, 69, 71, 70, 73

Offset: 1

Author

Zak Seidov, Nov 27 2007

Keywords

• nonn

Examples

			a(1)=1; then
a(2)=3 and a(3)=2 because p=3 is odd prime and p and p-1 are swapped.
		

Links

• G. C. Greubel, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A135761.

Programs

Mathematica

r=Range[100];Do[If[PrimeQ[r[[i]]],{r[[i]],r[[i-1]]}={r[[i-1]],r[[i]]}],{i,3,97,2}];r