A286457 Compound filter: a(n) = P(A078898(n), A246277(n)), with a(1) = 0, where P(n,k) is sequence A000027 used as a pairing function.

0, 1, 1, 5, 1, 13, 1, 25, 5, 41, 1, 61, 1, 85, 13, 113, 1, 145, 1, 181, 32, 221, 1, 265, 5, 313, 33, 365, 1, 421, 1, 481, 72, 545, 13, 613, 1, 685, 143, 761, 1, 841, 1, 925, 86, 1013, 1, 1105, 5, 1201, 219, 1301, 1, 1405, 32, 1513, 335, 1625, 1, 1741, 1, 1861, 201, 1985, 60, 2113, 1, 2245, 447, 2381, 1, 2521, 1, 2665, 223, 2813, 13, 2965, 1, 3121, 224, 3281

Offset

1,4

Links

Antti Karttunen, Table of n, a(n) for n = 1..10000

Eric Weisstein's World of Mathematics, Pairing Function

Formula

a(1) = 0 and for n > 1, a(n) = (1/2)*(2 + ((A078898(n)+A246277(n))^2) - A078898(n) - 3*A246277(n)).

Prog

(Scheme) (define (A286457 n) (if (= 1 n) 0 (* (/ 1 2) (+ (expt (+ (A078898 n) (A246277 n)) 2) (- (A078898 n)) (- (* 3 (A246277 n))) 2))))

Crossrefs

Cf. A000027, A078898, A246277, A280492.

Sequence in context: A094049 A286254 A322664 * A327766 A147348 A081224

Adjacent sequences: A286454 A286455 A286456 * A286458 A286459 A286460

Keyword

nonn

Author

Antti Karttunen, May 14 2017

Status

approved