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A286382 Compound filter: a(n) = P(A257993(n), A278226(n)), where P(n,k) is sequence A000027 used as a pairing function. 2

%I

%S 2,5,16,12,67,9,16,23,436,80,1771,18,67,80,1771,668,16111,48,277,302,

%T 7141,2630,64621,156,1129,1178,28681,10442,258841,14,16,23,436,80,

%U 1771,31,436,467,21946,1832,87991,94,1771,1832,87991,16292,793171,328,7141,7262,352381,64982,3173941,1228,28681,28922,1410361,259562,12698281,25,67,80,1771,668,16111

%N Compound filter: a(n) = P(A257993(n), A278226(n)), where P(n,k) is sequence A000027 used as a pairing function.

%H Antti Karttunen, <a href="/A286382/b286382.txt">Table of n, a(n) for n = 1..11550</a>

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/PairingFunction.html">Pairing Function</a>

%H <a href="/index/Pri#primorialbase">Index entries for sequences related to primorial base</a>

%F a(n) = (1/2)*(2 + ((A257993(n)+A278226(n))^2) - A257993(n) - 3*A278226(n)).

%o (Scheme) (define (A286382 n) (* (/ 1 2) (+ (expt (+ (A257993 n) (A278226 n)) 2) (- (A257993 n)) (- (* 3 (A278226 n))) 2)))

%Y Cf. A000027, A257993, A278226, A286142.

%Y Differs from A286381 for the first time at n=24, where a(24) = 156 while A286381(24) = 14.

%K nonn

%O 1,1

%A _Antti Karttunen_, May 08 2017

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Last modified June 20 08:43 EDT 2021. Contains 345162 sequences. (Running on oeis4.)