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%I #15 May 12 2017 03:44:38
%S 1,5,4,9,22,5,4,32,4,5,121,9,46,437,4,20,121,17,4,24,4,5,67,14,22,17,
%T 4,24,121,5,4,2562,211,5,121,9,4,107,121,14,7261,5,211,24,4,17,121,41,
%U 4,2280,4,9,254,5,4,32,4,17,67,24,22,17,631,35,121,5,121,783,4,5,121,32,211,2280,4,9,67,17,4,41,121,5,254,9,46,2280,4,140,121,5,4,24
%N Compound filter (2-adic valuation of n & 4k+1,4k+3 prime-signature combination of 2n-1): a(n) = P(A001511(n), A286364((2*n)-1)), where P(n,k) is sequence A000027 used as a pairing function.
%H Antti Karttunen, <a href="/A286461/b286461.txt">Table of n, a(n) for n = 1..10000</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/PairingFunction.html">Pairing Function</a>
%H Indranil Ghosh, <a href="/A286461/a286461.txt">Python program to generate the sequence</a>
%F a(n) = (1/2)*(2 + ((A001511(n)+A286364((2*n)-1))^2) - A001511(n) - 3*A286364((2*n)-1)).
%o (Scheme) (define (A286461 n) (* (/ 1 2) (+ (expt (+ (A001511 n) (A286364 (+ n n -1))) 2) (- (A001511 n)) (- (* 3 (A286364 (+ n n -1)))) 2)))
%Y Cf. A000027, A001511, A046523, A278223, A286161, A286364, A286371, A286372, A286463, A286465.
%K nonn
%O 1,2
%A _Antti Karttunen_, May 10 2017
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