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 A286566 Compound filter (prime signature of n & prime signature of the n-th Jacobsthal number): a(n) = P(A101296(n), A286566(n)), where P(n,k) is sequence A000027 used as a pairing function. 2
 1, 3, 5, 9, 5, 19, 5, 26, 18, 19, 5, 51, 5, 19, 40, 73, 5, 72, 5, 72, 40, 40, 5, 113, 31, 19, 83, 111, 8, 129, 5, 101, 32, 19, 32, 221, 8, 19, 40, 179, 8, 199, 5, 84, 159, 40, 8, 312, 13, 84, 82, 84, 8, 239, 49, 261, 32, 82, 23, 419, 5, 19, 159, 224, 82, 334, 8, 84, 32, 334, 8, 543, 8, 32, 84, 84, 82, 285, 5, 243, 332, 32, 57, 478, 40, 32, 32, 218, 23, 419, 82 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Here, instead of A046523 and A278165 we use as the components of a(n) their rgs-versions A101296 and A286565 because of the latter sequences' more moderate growth rates. LINKS Antti Karttunen, Table of n, a(n) for n = 1..1032 (computed using the b-file of A278165 provided by Hans Havermann) FORMULA a(n) = (1/2)*(2 + ((A101296(n)+A286565(n))^2) - A101296(n) - 3*A286565(n)). PROG (Scheme) (define (A286566 n) (* (/ 1 2) (+ (expt (+ (A101296 n) (A286565 n)) 2) (- (A101296 n)) (- (* 3 (A286565 n))) 2))) CROSSREFS Cf. A001045, A046523, A101296, A278165, A286565. Cf. A000978 (positions of 5's). Cf. A286467 (similar filter). Sequence in context: A199612 A076844 A198558 * A286467 A231736 A212437 Adjacent sequences:  A286563 A286564 A286565 * A286567 A286568 A286569 KEYWORD nonn AUTHOR Antti Karttunen, May 21 2017 STATUS approved

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Last modified July 21 19:25 EDT 2019. Contains 325199 sequences. (Running on oeis4.)