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A105363 Rearrangement of positive integers according to parity of (prime(n)-1)/2 (see comments). 1
1, 2, 3, 5, 4, 6, 7, 9, 8, 11, 10, 12, 13, 15, 14, 17, 16, 19, 21, 18, 23, 25, 20, 22, 24, 27, 29, 26, 28, 31, 33, 30, 35, 32, 37, 34, 39, 41, 36, 43, 38, 45, 40, 42, 47, 49, 51, 53, 44, 46, 55, 48, 57, 50, 59, 52, 61, 54, 56, 63, 58, 65, 67, 60, 62, 69, 64, 71, 66, 68, 73, 75 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

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

LINKS

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

MATHEMATICA

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

CROSSREFS

Cf. A105364.

Sequence in context: A131141 A130981 A074145 * A225047 A123917 A154444

Adjacent sequences:  A105360 A105361 A105362 * A105364 A105365 A105366

KEYWORD

nonn

AUTHOR

Zak Seidov, Apr 01 2005

STATUS

approved

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Last modified September 21 06:04 EDT 2014. Contains 247022 sequences.