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A062251 Take minimal prime q such that n(q+1)-1 is prime (A060324), that is, the smallest prime q so that n = (p+1)/(q+1) with p prime; sequence gives values of p. 8
2, 5, 11, 11, 19, 17, 41, 23, 53, 29, 43, 47, 103, 41, 59, 47, 67, 53, 113, 59, 83, 131, 137, 71, 149, 103, 107, 83, 173, 89, 433, 127, 131, 101, 139, 107, 443, 113, 233, 239, 163, 167, 257, 131, 179, 137, 281, 191, 293, 149, 1019, 311, 211, 431, 439, 167, 227 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

A conjecture of Schinzel, if true, would imply that such a p always exists.

LINKS

T. D. Noe, Table of n, a(n) for n = 1..10000

Matthew M. Conroy, A sequence related to a conjecture of Schinzel, J. Integ. Seqs. Vol. 4 (2001), #01.1.7.

Peter Luschny, Schinzel-Sierpinski conjecture and Calkin-Wilf tree.

A. Schinzel and W. Sierpiński, Sur certaines hypothèses concernant les nombres premiers, Acta Arithmetica 4 (1958), 185-208; erratum 5 (1958) p. 259.

FORMULA

a(n) = (A060324(n) + 1) * n - 1. - Reinhard Zumkeller, Aug 28 2014

EXAMPLE

1 = (2+1)/(2+1), 2 = (5+1)/(2+1), 3 = (11+1)/(3+1), 4 = (11+1)/(2+1), ...

MAPLE

a:= proc(n) local q;

       q:= 2;

       while not isprime(n*(q+1)-1) do

          q:= nextprime(q);

       od; n*(q+1)-1

    end:

seq(a(n), n=1..300);

MATHEMATICA

a[n_] := (q = 2; While[ ! PrimeQ[n*(q+1)-1], q = NextPrime[q]]; n*(q+1)-1); Table[a[n], {n, 1, 57}] (* Jean-François Alcover, Feb 17 2012, after Maple *)

PROG

(Haskell)

a062251 n = (a060324 n + 1) * n - 1 -- Reinhard Zumkeller, Aug 28 2014

CROSSREFS

Cf. A060424. Values of q are given in A060324.

Sequence in context: A300677 A079008 A144573 * A091114 A155767 A079782

Adjacent sequences:  A062248 A062249 A062250 * A062252 A062253 A062254

KEYWORD

nonn,nice,easy

AUTHOR

N. J. A. Sloane, Jul 01 2001

EXTENSIONS

More terms from Vladeta Jovovic, Jul 02 2001

STATUS

approved

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Last modified February 16 21:04 EST 2019. Contains 320191 sequences. (Running on oeis4.)