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First column of triangle A084408.
3

%I #5 Dec 05 2013 19:56:17

%S 1,2,5,4,13,10,31,20,30,42,61,55,109,70,88,108,181,126,277,148,174,

%T 201,397,225,255,287,318,348,547,382,733,417,456,496,535,576,947,621,

%U 666,711,1213,758,1499,805,858,910,1831,963,1020,1078,1137,1195,2207,1255

%N First column of triangle A084408.

%C a(n) is prime iff n is prime.

%F For n prime, a(n) = p(A034387(n)-n+1). For n composite, a(n) = A002808([n*(n+1)/2]-A034387(n)-n).

%Y Cf. A084408, A084409, A084411.

%K nonn,easy

%O 1,2

%A _Amarnath Murthy_, Jun 01 2003

%E Edited and extended by _David Wasserman_, Dec 27 2004