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A127639 A051731 * A127640, where A127640 = infinite lower triangular matrix with the sequence of primes in the main diagonal and the rest zeros.

%I A127639 #6 Aug 12 2015 20:48:37
%S A127639 2,2,3,2,0,5,2,3,0,7,2,0,0,0,11,2,3,5,0,0,13,2,0,0,0,0,0,17,2,3,0,7,0,
%T A127639 0,0,19,2,0,5,0,0,0,0,0,23,2,3,0,0,11,0,0,0,0,29,2,0,0,0,0,0,0,0,0,0,
%U A127639 31,2,3,5,7,0,13,0,0,0,0,0,37,2,0,0,0,0,0,0,0,0,0,0,0,41,2,3,0,0,0,0,17,0,0
%N A127639 A051731 * A127640, where A127640 = infinite lower triangular matrix with the sequence of primes in the main diagonal and the rest zeros.
%C A127639 Row sums = A007445, inverse Mobius transform of the primes: (2, 5, 7, 12, 13, 23, ...)
%e A127639 First few rows of the triangle are:
%e A127639 2;
%e A127639 2, 3;
%e A127639 2, 0, 5;
%e A127639 2, 3, 0, 7;
%e A127639 2, 0, 0, 0, 11;
%e A127639 2, 3, 5, 0, 0, 13;
%e A127639 ...
%p A127639 A051731 := proc(n,k) if n mod k = 0 then 1 ; else 0 ; fi ; end: A127639 := proc(n,k) A051731(n,k)*ithprime(k) ; end: for n from 1 to 16 do for k from 1 to n do printf("%d,", A127639(n,k)) ; od ; od ; # _R. J. Mathar_, Mar 14 2007
%Y A127639 Cf. A051731, A007445, A127639.
%K A127639 nonn,tabl,easy
%O A127639 1,1
%A A127639 _Gary W. Adamson_, Jan 21 2007
%E A127639 More terms from _R. J. Mathar_, Mar 14 2007