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A103934 Choose a(n) to be the smallest odd number not yet used such that: a(1) = 1, a(2n) = prime, a(2n+1) = composite and partial sums are alternately composite or prime. 1
1, 3, 9, 5, 25, 7, 21, 11, 15, 13, 27, 17, 39, 19, 45, 23, 33, 29, 55, 31, 35, 37, 57, 41, 49, 43, 119, 47, 51, 53, 91, 59, 77, 61, 125, 67, 143, 71, 69, 73, 65, 79, 63, 83, 75, 89, 121, 97, 81, 101, 99, 103, 87, 107, 117, 109, 135, 113, 93, 127, 111, 131, 129, 137, 115, 139 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..66.

CROSSREFS

Cf. A075593, A075594, A103824, A103825, A103935.

Sequence in context: A143218 A262024 A252117 * A186814 A077384 A122943

Adjacent sequences:  A103931 A103932 A103933 * A103935 A103936 A103937

KEYWORD

nonn

AUTHOR

Ray Chandler Feb 21 2005, based on a suggestion from Zak Seidov.

STATUS

approved

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Last modified April 11 03:12 EDT 2021. Contains 342886 sequences. (Running on oeis4.)