A277821 Inverse permutation to A277820.

1, 3, 2, 10, 4, 5, 6, 36, 9, 8, 28, 14, 15, 21, 7, 136, 11, 27, 120, 19, 91, 105, 20, 44, 45, 55, 13, 78, 35, 12, 66, 528, 77, 17, 496, 90, 435, 465, 43, 53, 325, 351, 54, 406, 18, 65, 378, 152, 153, 171, 16, 210, 135, 34, 190, 300, 26, 119, 276, 25, 231, 253, 104, 2080, 118, 275, 2016, 32, 1891, 1953, 252, 324, 1653, 1711, 33

Offset: 1

Author

Antti Karttunen, Nov 03 2016

Keywords

• nonn

Links

• Antti Karttunen, Table of n, a(n) for n = 1..16383
• Index entries for sequences that are permutations of the natural numbers

Crossrefs

Inverse: A277820.

Cf. A268671, A277818.

Programs

Scheme

(define (A277821 n) (let ((row (A268671 n)) (col (A277818 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 = A277818(n), and r = A268671(n).