|
| |
|
|
A083519
|
|
Beginning with 1, a(i)*a(j) + 2 is prime for all i,j, i != j.
|
|
0
| |
|
|
1, 3, 5, 9, 129, 1179, 21105, 96525, 419925, 13690959, 8403613179
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 0,2
|
|
|
EXAMPLE
| 1*3+2, 3*5+2,1*5 +2, etc. are primes.
9*1+2 = 11, 9*3+2=29, 9*5+2=47 are all prime numbers, therefore we can say that a(4) = 9.
|
|
|
MATHEMATICA
| a = {1}; For[n = 2, n < 1000000, n++, b = Table[a[[i]]*n + 2, {i, 1, Length[ a]}]; If[Union[PrimeQ[b], PrimeQ[b]] == {True}, AppendTo[a, n]]]; a - Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Jun 02 2007
|
|
|
CROSSREFS
| Cf. A083518.
Sequence in context: A098339 A121622 A188983 * A173706 A176629 A069193
Adjacent sequences: A083516 A083517 A083518 * A083520 A083521 A083522
|
|
|
KEYWORD
| hard,more,nonn
|
|
|
AUTHOR
| Amarnath Murthy and Meenakshi Srikanth (amarnath_murthy(AT)yahoo.com), May 05 2003
|
|
|
EXTENSIONS
| Corrected and extended by Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Jun 02 2007
a(10) from Donovan Johnson (donovan.johnson(AT)yahoo.com), Nov 11 2008
|
| |
|
|
