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A060327 Primes the sum of both two and three consecutive composite numbers. 2
31, 41, 67, 71, 109, 113, 131, 139, 199, 211, 239, 251, 269, 293, 311, 337, 379, 409, 419, 487, 491, 499, 521, 571, 599, 631, 701, 751, 769, 773, 787, 829, 881, 919, 941, 953, 991, 1009, 1013, 1039, 1049, 1061, 1103, 1117, 1151, 1193, 1229, 1291, 1301 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..49.

EXAMPLE

a(2) = 41 which is equal to 20+21 and 12+14+15.

MATHEMATICA

composite[ n_Integer ] := (k = n + PrimePi[ n ] + 1; While[ k - PrimePi[ k ] - 1 != n, k++ ]; k); a = {}; Do[ p = composite[ n ] + composite[ n + 1 ]; If[ PrimeQ[ p ], a = Append[ a, p ] ], {n, 1, 1000} ]; b = {}; Do[ p = composite[ n ] + composite[ n + 1 ] + composite[ n + 2 ]; If[ PrimeQ[ p ], b = Append[ b, p ] ], {n, 1, 1000} ]; Intersection[ a, b ]

CROSSREFS

Sequence in context: A089721 A089442 A243704 * A202286 A285805 A141180

Adjacent sequences:  A060324 A060325 A060326 * A060328 A060329 A060330

KEYWORD

nonn

AUTHOR

Robert G. Wilson v, Mar 30 2001

STATUS

approved

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Last modified December 4 15:36 EST 2021. Contains 349526 sequences. (Running on oeis4.)