

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
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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



