A267102 Inverse permutation to A265901.

1, 2, 3, 4, 6, 10, 5, 7, 15, 21, 28, 9, 36, 14, 8, 11, 45, 55, 66, 78, 20, 91, 105, 27, 120, 35, 13, 136, 44, 19, 12, 16, 153, 171, 190, 210, 231, 54, 253, 276, 300, 65, 325, 351, 77, 378, 90, 26, 406, 435, 104, 465, 119, 34, 496, 135, 43, 18, 528, 152, 53, 25, 17, 22, 561, 595, 630, 666, 703, 741, 170, 780, 820

Offset: 1

Author

Antti Karttunen, Jan 10 2016

Keywords

• nonn

Links

• Antti Karttunen, Table of n, a(n) for n = 1..10000
• Index entries for sequences that are permutations of the natural numbers

Crossrefs

Inverse: A265901.

Cf. A162598, A265332.

Programs

Scheme

(define (A267102 n) (let ((col (A265332 n)) (row (A162598 n))) (* (/ 1 2) (- (expt (+ row col) 2) row col col col -2))))

Formula

a(n) = (1/2) * ((c+r)^2 - r - 3*c + 2), where c = A265332(n), and r = A162598(n).