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A267102
Inverse permutation to A265901.
2
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
1,2
FORMULA
a(n) = (1/2) * ((c+r)^2 - r - 3*c + 2), where c = A265332(n), and r = A162598(n).
PROG
(Scheme) (define (A267102 n) (let ((col (A265332 n)) (row (A162598 n))) (* (/ 1 2) (- (expt (+ row col) 2) row col col col -2))))
CROSSREFS
Inverse: A265901.
Sequence in context: A108858 A294688 A094859 * A122397 A359679 A339670
KEYWORD
nonn
AUTHOR
Antti Karttunen, Jan 10 2016
STATUS
approved