A286458 Compound filter: a(n) = P(A286448(n), A286449(n)), where P(n,k) is sequence A000027 used as a pairing function.

1, 1, 2, 3, 13, 25, 24, 15, 61, 5, 85, 113, 112, 64, 87, 55, 201, 243, 242, 313, 204, 393, 451, 513, 137, 22, 613, 250, 723, 651, 842, 276, 67, 844, 196, 1015, 1107, 657, 196, 1253, 1355, 1020, 1407, 559, 812, 795, 1744, 1864, 833, 2051, 1062, 101, 2181, 1363, 2384, 2524, 597, 2741, 2891, 3045, 3203, 1935, 1756, 1081, 1249, 1938, 3703, 1534, 441

Offset: 1

Author

Antti Karttunen, May 14 2017

Keywords

• nonn

Comments

For all i, j: a(i) = a(j) => A286385(i) = A286385(j).

Links

• Antti Karttunen, Table of n, a(n) for n = 1..10000
• Eric Weisstein's World of Mathematics, Pairing Function

Crossrefs

Cf. A000027, A033879, A048673, A252748, A286385, A286448, A286449, A286459.

Programs

Scheme

(define (A286458 n) (* (/ 1 2) (+ (expt (+ (A286448 n) (A286449 n)) 2) (- (A286448 n)) (- (* 3 (A286449 n))) 2)))

Formula

a(n) = (1/2)*(2 + ((A286448(n)+A286449(n))^2) - A286448(n) - 3*A286449(n)).

a(n) = A286459(A048673(n)).