This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A266638 #10 Jan 30 2016 03:11:17 %S A266638 1,2,3,4,5,7,6,9,10,13,8,16,12,15,19,22,11,27,17,31,25,29,18,36,20,40, %T A266638 24,49,26,32,54,46,51,34,62,37,14,68,43,81,35,47,23,55,88,76,33,83,58, %U A266638 99,64,28,44,107,72,127,61,77,42,91,53,136,121,56,130,94,21,151,101,50,65,73,161,114,189,98,38 %N A266638 a(1) = 1, a(ludic(n)) = (ludic(3+a(n-1))-1)/2, a(nonludic(n)) = A266410(a(n)), where ludic(n) = n-th ludic number A003309, nonludic(n) = n-th nonludic number A192607 and A266410 = numbers n such that 2n+1 is nonludic. %H A266638 Antti Karttunen, <a href="/A266638/b266638.txt">Table of n, a(n) for n = 1..10000</a> %H A266638 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %F A266638 a(1) = 1; for n > 1, if A192490(n) = 1 [when n is one of Ludic numbers, A003309] a(n) = A266409(1+a(A192512(n)-1)), otherwise a(n) = A266410(a(A236863(n))). %F A266638 As a composition of related permutations: %F A266638 a(n) = A266418(A237427(n)). %o A266638 (Scheme, with memoization-macro definec) %o A266638 (definec (A266638 n) (cond ((<= n 1) n) ((= 1 (A192490 n)) (A266409 (+ 1 (A266638 (- (A192512 n) 1))))) (else (A266410 (A266638 (A236863 n)))))) %Y A266638 Inverse: A266637. %Y A266638 Cf. A003309, A192490, A192512, A236863, A266409, A266410. %Y A266638 Related or similar permutations: A237427, A266418. %K A266638 nonn %O A266638 1,2 %A A266638 _Antti Karttunen_, Jan 28 2016