A087572 - OEIS

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A087572

Smallest prime of the form n + (n-1) + (n-2) + ...(n-k), k < n, or 0 if no such prime exists.

1

0, 2, 3, 7, 5, 11, 7, 0, 17, 19, 11, 23, 13, 0, 29, 31, 17, 0, 19, 0, 41, 43, 23, 47, 0, 0, 53, 0, 29, 59, 31, 0, 0, 67, 0, 71, 37, 0, 0, 79, 41, 83, 43, 0, 89, 0, 47, 0, 97, 0, 101, 103, 53, 107, 109, 0, 113, 0, 59, 0, 61, 0, 0, 127, 0, 131, 67, 0, 137, 139, 71, 0, 73, 0, 149, 151, 0

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OFFSET

1,2

COMMENTS

Trivially a(n) = 0 if n and 2n-1 both are composite. i.e. (k = 0 or 1.)

If a(n) > 0 then a(n) = A034694(n-1). - David Wasserman, Jun 07 2005

LINKS

Table of n, a(n) for n=1..77.

CROSSREFS

Sequence in context: A045790 A159842 A085102 * A085107 A358242 A241082

Adjacent sequences: A087569 A087570 A087571 * A087573 A087574 A087575

KEYWORD

nonn

AUTHOR

Amarnath Murthy, Sep 17 2003

EXTENSIONS

More terms from David Wasserman, Jun 07 2005

STATUS

approved