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%I #24 Apr 05 2018 20:33:17
%S 1,1,1,2,1,3,1,4,2,5,1,6,1,7,3,8,1,9,2,10,4,11,1,12,1,13,5,14,1,15,2,
%T 16,6,17,3,18,1,19,7,20,1,21,1,22,8,23,1,24,4,25,9,26,1,27,2,28,10,29,
%U 3,30,1,31,11,32,5,33,1,34,12,35,1,36,2,37,13,38,1,39,6,40,14,41,1,42,4,43,15,44,1,45,1,46,16,47,7,48,1,49,17,50,2
%N Column index to A255127: a(1) = 1; for n > 1, a(n) = the position at the stage where n is removed in the sieve which produces Ludic numbers.
%C Ordinal transform of A272565 (Ludic factor), and also of A260738. - _Antti Karttunen_, Apr 03 2018
%H Antti Karttunen, <a href="/A260739/b260739.txt">Table of n, a(n) for n = 1..10105</a>
%F Other identities. For all n >= 2:
%F a(A003309(n)) = 1. [In Ludic sieve each Ludic number (after 1) is the first among the numbers removed at stage k.]
%F a(A254100(n)) = 2.
%F A255127(A260738(n), a(n)) = n.
%F For n > 1, A001511(a(n)) = A302035(n). - _Antti Karttunen_, Apr 03 2018
%o (Scheme)
%o (define (A260739 n) (cond ((= 1 n) 1) ((even? n) (/ n 2)) (else (let searchrow ((row 2)) (let searchcol ((col 1)) (cond ((>= (A255127bi row col) n) (if (= (A255127bi row col) n) col (searchrow (+ 1 row)))) (else (searchcol (+ 1 col))))))))) ;; Code for A255127bi given in A255127.
%Y Column index to array A255127.
%Y Cf. A003309, A254100, A272565.
%Y Cf. A260738 (corresponding row index).
%Y Cf. A302035, A302036 (positions of terms that are powers of 2).
%Y Cf. A078898, A246277, A260429, A260439 for column indices to other arrays similar to A255127.
%Y Differs from A246277 (and also after the initial term from A078898) for the first time at n=19.
%K nonn
%O 1,4
%A _Antti Karttunen_, Jul 30 2015
%E Term a(1) changed from 0 to 1 to match with the definition of A078898 and the interpretation as an ordinal transform - _Antti Karttunen_, Apr 03 2018
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