A265348 - OEIS

%I #5 Dec 29 2015 03:20:22

%S 1,2,3,4,10,5,6,7,15,9,55,8,28,44,66,11,91,20,36,13,21,14,210,12,45,

%T 35,105,19,406,27,190,22,435,230,703,26,253,299,78,18,1711,170,325,76,

%U 741,54,496,17,136,377,528,43,820,119,276,25,153,65,2145,34,300,209,120,16,1596,77,231,64,1128,104,1770,33,351,275,171,53,2775,90,378,24,861

%N Inverse permutation to A265347.

%H Antti Karttunen, <a href="/A265348/b265348.txt">Table of n, a(n) for n = 1..10328</a>

%H <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a>

%F a(n) = (1/2) * ((c+r)^2 - r - 3*c + 2), where c = A265331(n), and r = A265911(n).

%o (Scheme) (define (A265348 n) (let ((row (A265911 n)) (col (A265331 n))) (* (/ 1 2) (- (expt (+ row col) 2) row col col col -2))))

%Y Inverse: A265347.

%Y Cf. A265331, A265911.

%K nonn

%O 1,2

%A _Antti Karttunen_, Dec 18 2015