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A130676 Numbers n for which either 16*n^2-6*n+1 or 16*n^2-10*n-1 or both is/are prime. 0
1, 2, 3, 4, 5, 6, 7, 8, 10, 11, 15, 16, 17, 18, 20, 22, 23, 25, 27, 28, 30, 32, 33, 35, 36, 37, 38, 39, 42, 43, 44, 46, 48, 50, 52, 57, 59, 60, 63, 65, 67, 68, 70, 71, 72, 73, 76, 80, 81, 85, 87, 88, 90, 92, 93, 94, 95, 98, 101, 102, 103, 104, 105, 108, 110, 112, 113, 115, 118, 120, 123, 125, 128, 129, 132, 134 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Consider the two forms (4*n-2)*4*n +- (2*n+1), where "+-" generates two different terms 16*n^2-6*n+1 and 16*n^2-10*n-1 for n=1,2,3,...

If at least one of the two numbers is prime, n is inserted into the sequence.

LINKS

Table of n, a(n) for n=1..76.

EXAMPLE

For n=20, 16*20^2 - 10*20 - 1= (4*20-2)*4*20-(2*20+1) = 6199 is prime, which adds 20 to the sequence.

For n=15, 16*15^2 - 6*15 +1= (4*15-2)*4*15 +(2*15+1) = 3511 is prime, which adds 15 to the sequence.

CROSSREFS

Sequence in context: A044919 A011871 A229769 * A039227 A257727 A039273

Adjacent sequences:  A130673 A130674 A130675 * A130677 A130678 A130679

KEYWORD

easy,nonn,less

AUTHOR

J. M. Bergot, Jun 28 2007

EXTENSIONS

Edited and extended. - R. J. Mathar, Jul 10 2011

STATUS

approved

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Last modified April 11 22:01 EDT 2021. Contains 342888 sequences. (Running on oeis4.)