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Group the natural numbers so that the n-th group contains n numbers whose sum as well as the group product + 1 is prime. Sequence contains the last term of each group.
9

%I #7 Dec 05 2013 19:56:46

%S 2,4,10,9,23,28,29,47,115,71,88,214,215,188,341,133,220,372,250,321,

%T 227,311,281,310,592,857,691,406,470,483,904,903,707,601,876,727,726,

%U 1299,828,925,1217,1254,963,1426,1213,1394,2108,1356,1448,1286,1564,1455

%N Group the natural numbers so that the n-th group contains n numbers whose sum as well as the group product + 1 is prime. Sequence contains the last term of each group.

%C Sequence is underdefined. The original author may have intended to say that the terms must be distinct and minimal; perhaps he should clarify. - _Jonathan Vos Post_, Mar 22 2006

%C See A092944 for additional clarification of definition.

%e a(6) = 28 because 15+16+17+18+19+28 = 113 is prime and 15*16*17*18*19*28 + 1 = 39070081 is prime.

%Y Cf. A092944, A092946, A092947.

%K nonn

%O 1,1

%A _Amarnath Murthy_, Mar 23 2004

%E a(6) from _Jonathan Vos Post_, Mar 22 2006

%E Edited and extended by _Ray Chandler_, May 07 2008