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A254047
Inverse permutation to A191450.
5
1, 2, 3, 6, 4, 10, 15, 5, 21, 28, 9, 36, 45, 7, 55, 66, 14, 78, 91, 20, 105, 120, 8, 136, 153, 27, 171, 190, 35, 210, 231, 13, 253, 276, 44, 300, 325, 54, 351, 378, 11, 406, 435, 65, 465, 496, 77, 528, 561, 19, 595, 630, 90, 666, 703, 104, 741, 780, 26, 820, 861, 119, 903, 946, 135, 990, 1035, 12, 1081, 1128, 152, 1176, 1225, 170, 1275, 1326, 34
OFFSET
1,2
PROG
(Scheme)
(define (A254047 n) (let ((x (A253887 n)) (y (A254046 n))) (* (/ 1 2) (- (expt (+ x y) 2) x y y y -2))))
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Jan 24 2015
STATUS
approved