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A166686 If m-th composite is the product of k1-th prime, k2-th prime,.., kr-th prime and m+k1+k2+..+kr is prime then set a(n)=m. 0
1, 2, 8, 9, 13, 14, 16, 17, 30, 31, 33, 34, 53, 59, 61, 65, 80, 85, 89, 92, 94, 96, 97, 103, 113, 116, 117, 121, 127, 128, 142, 143, 160, 163, 180, 182, 188, 189, 206, 208, 216, 221, 227, 235, 236, 242, 255, 256, 261, 262, 265, 271, 294, 297, 298, 300, 304, 315 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..58.

EXAMPLE

Since 1th composite=4=2*2=(1th prime)*(1th prime) and 1+1+1=3(prime) then a(1)=1. Since 2th composite=6=2*3=(1th prime)*(2th prime) and 2+1+2=5(prime) then a(2)=2.

CROSSREFS

Cf. A000040, A002808.

Sequence in context: A081381 A235524 A239133 * A064833 A073606 A047353

Adjacent sequences:  A166683 A166684 A166685 * A166687 A166688 A166689

KEYWORD

nonn

AUTHOR

Juri-Stepan Gerasimov, Oct 18 2009

EXTENSIONS

6 removed, 49 removed, 94 inserted, 102 removed, 103 inserted by R. J. Mathar, Oct 28 2009

STATUS

approved

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Last modified April 23 17:46 EDT 2014. Contains 240946 sequences.