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A128994 First of three consecutive pairwise coprime numbers such that the product of any two plus the third is a prime. 0
1, 2, 3, 5, 6, 8, 19, 25, 32, 38, 53, 84, 110, 114, 119, 122, 125, 129, 133, 159, 170, 175, 229, 235, 263, 302, 313, 320, 385, 419, 489, 495, 543, 572, 593, 643, 749, 786, 815, 866, 929, 949, 966, 1122, 1123, 1173, 1254, 1365, 1459, 1470, 1508, 1542, 1565, 1584 (list; graph; refs; listen; history; internal format)
OFFSET

1,2

EXAMPLE

For 6 the next two numbers such that all are pairwise coprime are 7 and 11.

All three numbers 6*7+11, 6*11+7, 7*11+6 are prime, therefore 6 is in the sequence.

MATHEMATICA

l = {}; For[n = 1, n < 2000, n++, a = n; i = 1; While[Not[GCD[a, a + i]], i++ ]; b = a + i; i = 1; While[Not[GCD[a, b + i] == 1 && GCD[b, b + i] == 1], i++ ]; c = b + i; If[PrimeQ[a*b + c] && PrimeQ[a*c + b] && PrimeQ[b*c + a], AppendTo[l, n]]]; l

CROSSREFS

Sequence in context: A088497 A088485 A194626 * A098211 A073673 A179217

Adjacent sequences:  A128991 A128992 A128993 * A128995 A128996 A128997

KEYWORD

nonn

AUTHOR

J. M. Bergot (thekingfishb(AT)yahoo.ca), Apr 30 2007

EXTENSIONS

Edited and extended by Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Aug 07 2007

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Last modified February 15 08:20 EST 2012. Contains 205729 sequences.