%I #8 Nov 27 2015 00:17:41
%S 1,1,2,1,2,1,3,1,2,3,4,2,5,1,3,2,3,1,4,1,4,2,5,1,2,3,4,1,5,1,6,1,3,2,
%T 4,1,2,1,2,2,3,1,4,1,2,2,3,2,4,3,4,1,5,1,6,2,7,1,3,1,8,1,2,2,3,1,3,1,
%U 3,2,4,1,4,1,3,2,4,1,5,1,6,3,4,2,4,3,4,3,5,2,6,3,4,4,5,5,5,2,4,3,6,2,5,3,7,3,5,4,8,3,6,4,7,2,7,3,8,4,4,2,7
%N a(n) = number of integers k <= n for which A155043(k) = A155043(n).
%C a(n) = one-based index of n in row A155043(n) of table A263265.
%H Antti Karttunen, <a href="/A263259/b263259.txt">Table of n, a(n) for n = 0..12333</a>
%F Other identities. For all n >= 0:
%F a(A261089(n)) = 1.
%F a(A262503(n)) = A262507(n).
%F A263265(A155043(n), a(n)) = n.
%o (Scheme, with memoizing definec-macro)
%o (definec (A263259 n) (cond ((zero? n) 1) ((= 1 (- (A263089 n) (A263089 (- n 1)))) 1) (else (let ((d (A155043 n))) (let loop ((k (- n 1))) (if (= (A155043 k) d) (+ 1 (A263259 k)) (loop (- k 1))))))))
%Y Cf. A000005, A155043, A261089, A262503, A262507, A263089, A263265, A263279.
%K nonn
%O 0,3
%A _Antti Karttunen_, Nov 24 2015