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A109854 Least K such that K*(3^(n+j))+1 is prime for j=0 to 4. 0
20, 110, 110, 20980, 29580, 9860, 150780, 50260, 217490, 657770, 426650, 1999330, 2942960, 1295490, 431830, 437570, 436450, 7564120, 6449730 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..19.

EXAMPLE

20*(3^(1+0))+1=61 prime

20*(3^(1+1))+1=181 prime

20*(3^(1+2))+1=541 prime

20*(3^(1+3))+1=1621 prime

20*(3^(1+4))+1=4861 prime

so for n=1 K=20.

CROSSREFS

Sequence in context: A232586 A189437 A285698 * A008383 A024192 A309781

Adjacent sequences:  A109851 A109852 A109853 * A109855 A109856 A109857

KEYWORD

nonn

AUTHOR

Pierre CAMI, Aug 31 2005

STATUS

approved

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Last modified December 3 20:35 EST 2021. Contains 349468 sequences. (Running on oeis4.)