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A087548 Beginning with 1, smallest multiple of n such that a(n)*a(n-1) + 1 is a prime. 0
1, 2, 3, 4, 10, 6, 7, 16, 27, 10, 33, 12, 13, 42, 15, 16, 85, 18, 114, 20, 21, 22, 46, 72, 25, 52, 189, 84, 29, 60, 31, 192, 33, 34, 70, 36, 185, 228, 39, 80, 164, 420, 43, 220, 45, 138, 94, 48, 147, 50, 51, 312, 106, 270, 55, 168, 171, 348, 59, 60, 122, 620, 126, 256, 195 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..65.

MAPLE

a[1] := 1:for n from 2 to 120 do l := 1:while(not isprime(a[n-1]*l*n+1)) do l := l+1: od:a[n] := l*n:od:seq(a[j], j=1..120); # Sascha Kurz

CROSSREFS

Sequence in context: A140598 A129920 A065634 * A111619 A241083 A143178

Adjacent sequences:  A087545 A087546 A087547 * A087549 A087550 A087551

KEYWORD

nonn

AUTHOR

Amarnath Murthy, Sep 13 2003

EXTENSIONS

Corrected and extended by Sascha Kurz, Sep 22 2003

STATUS

approved

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Last modified March 28 05:29 EDT 2020. Contains 333073 sequences. (Running on oeis4.)