A255560 - OEIS

%I #12 Apr 19 2015 00:53:21

%S 1,2,1,2,3,4,1,2,5,3,4,6,7,8,1,2,9,5,3,10,11,4,6,12,7,8,13,14,15,16,1,

%T 2,17,9,5,18,19,3,10,20,11,4,21,22,23,6,12,24,7,8,25,26,13,14,27,15,

%U 16,28,29,30,31,32,1,2,33,17,9,34,35,5,18,36,19,3,37,38,39,10,20,40,11,4,41,42,21,22,43,23,6

%N One-based row index of n in array A255555.

%C Equally: One-based column index of n in array A255557.

%H Antti Karttunen, <a href="/A255560/b255560.txt">Table of n, a(n) for n = 1..8192</a>

%F a(1) = 1; for n > 1, if A213714(n) = 0 [i.e., if n is one of the terms of A055938], then a(n) = 1+A234017(n), otherwise a(n) = a(A213714(n)-1).

%F In other words, a(1) = 1, and for n > 1, if n = A055938(k) for some k, then a(n) = k+1, otherwise it must be that n = A005187(h) for some h, in which case a(n) = a(h-1).

%o (Scheme, with memoization-macro definec)

%o (definec (A255560 n) (cond ((= 1 n) n) ((zero? (A213714 n)) (+ 1 (A234017 n))) (else (A255560 (+ -1 (A213714 n))))))

%Y Cf. A005187, A055938, A213714, A234017, A255555, A255557.

%Y Cf. also A255559 (corresponding column index).

%Y Cf. A254112, A256990.

%K nonn

%O 1,2

%A _Antti Karttunen_, Apr 14 2015