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A143393 Least prime a(n) such that a(n)*(a(n)+p(n))-1 is prime with p(i)=i-th prime. 2
2, 3, 2, 2, 3, 2, 2, 2, 5, 2, 3, 7, 3, 2, 2, 2, 7, 3, 2, 5, 2, 5, 3, 2, 2, 3, 3, 7, 5, 2, 2, 3, 2, 2, 5, 3, 2, 5, 2, 2, 5, 5, 11, 2, 2, 2, 3, 2, 2, 2, 11, 7, 5, 3, 7, 3, 2, 3, 2, 5, 2, 3, 2, 3, 3, 5, 11, 2, 3, 2, 2, 29, 3, 5, 2, 2, 37, 2, 5, 2, 11, 5, 3, 3, 2, 5, 5, 5, 23, 2, 2, 17, 2, 3, 7, 2, 2, 3, 2, 5, 2, 2 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

LINKS

Pierre CAMI, Table of n, a(n) for n = 1..12250

EXAMPLE

2*(2+2)-1=7 prime so a(1)=2 as p(1)=2

2*(2+3)-1=9 composite

3*(3+3)-1=17 prime so a(2)=3 as p(2)=3

CROSSREFS

Cf. A143394.

Sequence in context: A128049 A104543 A054988 * A166497 A116909 A085239

Adjacent sequences:  A143390 A143391 A143392 * A143394 A143395 A143396

KEYWORD

nonn

AUTHOR

Pierre CAMI (pierre-cami(AT)bbox.fr), Aug 12 2008

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Last modified February 15 12:59 EST 2012. Contains 205788 sequences.