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A242383 revision #8

A242383

Lesser of consecutive primes whose average is an oblong number.

5, 11, 29, 41, 53, 71, 239, 337, 419, 461, 503, 547, 599, 647, 863, 1051, 1187, 1481, 1721, 1801, 2549, 2647, 2969, 3539, 4421, 6317, 7129, 8009, 10301, 12653, 13567, 14033, 17291, 18353, 19181, 19457, 20021, 22943, 23561, 24179, 27059, 29063, 29753, 31151, 33301, 35153

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..46.

EXAMPLE

53 is in the sequence because it is prime, nextprime(53) = 59 and (53+59)/2 = 56 = 8*7, an oblong number.

PROG

(PARI){for(i=3, 10^5, if(isprime(i), k=(i+nextprime(i+1))/4; if(issquare(8*k+1), print1(i, ", "))))}

CROSSREFS

Cf. A154634.

Sequence in context: A019345 A279067 A049489 * A141785 A144311 A074367

Adjacent sequences: A242380 A242381 A242382 * A242384 A242385 A242386

KEYWORD

nonn

AUTHOR

Antonio Roldán, May 12 2014

STATUS

editing