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A074846 a(n) > n > 0 and n*a(n)+1 is the smallest prime. +0
1
2, 3, 4, 7, 6, 7, 10, 9, 12, 13, 18, 13, 24, 15, 16, 21, 18, 21, 22, 2, 22, 28, 26, 25, 28, 33, 28, 34, 32, 33, 36, 36, 34, 37, 42, 43, 40, 39, 48, 43, 42, 46, 46, 47, 48, 51, 50, 54, 52, 51, 56, 55, 56, 55, 58, 60, 58, 61, 60, 67, 66, 63, 66, 67, 68, 67, 70, 75, 70, 79, 72, 79 (list; graph; listen)
OFFSET

1,1

COMMENT

For any integer n there are infinite number of primes of the form n*a+q. Here we consider the case q = 1 and the smallest a > n > 0. In this case for each n we have unique a (even for n=0 we have a(0)=1). But value of the a may be the same for different n, e.g. a(4)=a(6)=7, a(10)=a(12)=13, a(11)=a(17)=18 etc.

EXAMPLE

a(1)=2 because 1*2+1=3 is the smallest prime of the form 1*a+1 with a>1, a(4)=7 because 4*7+1=29 is the smallest prime of the form 4*a+1 with a>4, a(100)=103 because 100*103 is the smallest prime of the form 100*a with a>100.

CROSSREFS

Sequence in context: A122155 A106454 A132075 this_sequence A120225 A130685 A125595

Adjacent sequences: A074843 A074844 A074845 this_sequence A074847 A074848 A074849

KEYWORD

nonn

AUTHOR

Zak Seidov (zakseidov(AT)yahoo.com), Sep 10 2002

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Last modified December 5 20:25 EST 2009. Contains 170428 sequences.


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