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A086531 a(1) = 9; a(n+1) is the least odd composite number not already used such that (a(n+1)+a(n))/2 is prime. 1
9, 25, 21, 65, 57, 49, 33, 85, 81, 77, 45, 121, 93, 125, 69, 133, 129, 145, 117, 161, 141, 185, 177, 169, 105, 209, 153, 205, 189, 265, 201, 221, 165, 217, 237, 245, 213, 253, 225, 289, 249, 305, 261, 301, 285, 329, 297, 325, 309, 365, 333, 341, 273, 361, 345 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Appears to contain all composite numbers of the form 4k+1. - David Wasserman, Mar 15 2005

LINKS

Table of n, a(n) for n=1..55.

CROSSREFS

Cf. A086532.

Sequence in context: A096757 A101158 A113496 * A089091 A282176 A204918

Adjacent sequences:  A086528 A086529 A086530 * A086532 A086533 A086534

KEYWORD

nonn

AUTHOR

Amarnath Murthy, Jul 31 2003

EXTENSIONS

More terms from David Wasserman, Mar 15 2005

STATUS

approved

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Last modified March 30 12:10 EDT 2020. Contains 333125 sequences. (Running on oeis4.)