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A135762
Start with sequence of positive integers, then swap a(i) and a(i-1) if a(i) is an odd prime.
2
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
1,2
LINKS
EXAMPLE
a(1)=1; then
a(2)=3 and a(3)=2 because p=3 is odd prime and p and p-1 are swapped.
MATHEMATICA
r=Range[100]; Do[If[PrimeQ[r[[i]]], {r[[i]], r[[i-1]]}={r[[i-1]], r[[i]]}], {i, 3, 97, 2}]; r
CROSSREFS
Cf. A135761.
Sequence in context: A372358 A301941 A344547 * A344548 A341903 A066250
KEYWORD
nonn
AUTHOR
Zak Seidov, Nov 27 2007
STATUS
approved