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A242385 Lesser of consecutive primes such that their average is of the form k*(k+2), for some integer k. 1
13, 97, 113, 193, 283, 397, 479, 673, 953, 1439, 1597, 2297, 2699, 3469, 4219, 4483, 5323, 7219, 8273, 9209, 9403, 10799, 12097, 13219, 14879, 15373, 15619, 21313, 23399, 26237, 27883, 32029, 32749, 34217, 37243, 39989, 41203, 42433, 43669, 46219, 55219, 60509, 62497 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..43.

EXAMPLE

193 is in the sequence because 193 is prime, nextprime(193) = 197, and (193+197)/2 = 195 = 13*(13+2).

PROG

(PARI) {k=2; while(k<10^5, l=nextprime(k+1); if(issquare((k+l)/2+1), print1(k, ", ")); k=l)}

CROSSREFS

Cf. A242384.

Sequence in context: A297081 A297603 A094499 * A141894 A275879 A160554

Adjacent sequences:  A242382 A242383 A242384 * A242386 A242387 A242388

KEYWORD

nonn

AUTHOR

Antonio Roldán, May 12 2014

STATUS

approved

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Last modified January 21 13:38 EST 2018. Contains 297994 sequences.