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A207338 Triangle read by rows in which row n lists the prime factors of n with repetition, with a(1) = 1, but with the primes of the form 4k + 1 multiplied by -1.

%I A207338 #22 Apr 16 2012 14:09:51
%S A207338 1,2,3,2,2,-5,2,3,7,2,2,2,3,3,2,-5,11,2,2,3,-13,2,7,3,-5,2,2,2,2,-17,
%T A207338 2,3,3,19,2,2,-5,3,7,2,11,23,2,2,2,3,-5,-5,2,-13,3,3,3,2,2,7,-29,2,3,
%U A207338 -5,31,2,2,2,2,2,3,11,2,-17,-5,7,2,2,3,3,-37
%N A207338 Triangle read by rows in which row n lists the prime factors of n with repetition, with a(1) = 1, but with the primes of the form 4k + 1 multiplied by -1.
%C A207338 The row products of triangle give A209662. Also the row products of triangle divided by n give A209661. The mentioned sequences are related to an infinite series which is equal to pi, due to Leonhard Euler.
%e A207338 Written as a triangle begins:
%e A207338 1;
%e A207338 2;
%e A207338 3;
%e A207338 2, 2;
%e A207338 -5;
%e A207338 2, 3;
%e A207338 7;
%e A207338 2, 2, 2;
%e A207338 3, 3;
%e A207338 2, -5;
%e A207338 11;
%e A207338 2, 2, 3;
%e A207338 -13;
%e A207338 2, 7;
%e A207338 3, -5;
%e A207338 2, 2, 2, 2;
%Y A207338 Absolute values give A027746.
%Y A207338 Cf. A002144, A002145, A209661, A209662.
%K A207338 sign,tabf
%O A207338 1,2
%A A207338 _Omar E. Pol_, Apr 15 2012