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 A039970 An example of a d-perfect sequence: a(2*n) = 0, a(2*n+1) = Catalan(n) mod 3. 1
 1, 0, 1, 0, 2, 0, 2, 0, 2, 0, 0, 0, 0, 0, 0, 0, 2, 0, 2, 0, 2, 0, 1, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 2, 0, 2, 0, 1, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 1, 0, 2, 0, 2, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,5 LINKS Antti Karttunen, Table of n, a(n) for n = 1..65537 D. Kohel, S. Ling and C. Xing, Explicit Sequence Expansions, in Sequences and their Applications, C. Ding, T. Helleseth, and H. Niederreiter, eds., Proceedings of SETA'98 (Singapore, 1998), 308-317, 1999. DOI: 10.1007/978-1-4471-0551-0_23 FORMULA a(2*n) = 0, a(2*n+1) = A039969(n). - Christian G. Bower, Jun 12 2005, sign edited because of changed offset of A039969. - Antti Karttunen, Feb 13 2019 MATHEMATICA Table[If[IntegerQ[n/2], 0, Mod[CatalanNumber[(n-1)/2], 3]], {n, 1, 100}] (* G. C. Greubel, Feb 13 2019 *) PROG (PARI) A039969(n) = ((binomial(2*n, n)/(n+1))%3); A039970(n) = if(n%2, A039969((n-1)/2), 0); \\ Antti Karttunen, Feb 13 2019 (Sage) def A039970(n):     if (mod(n, 2)==0):         return 0     else:         return mod(catalan_number((n-1)/2), 3) [A039970(n) for n in (1..100)] # G. C. Greubel, Feb 13 2019 (MAGMA) [n mod 2 eq 0 select 0 else Catalan(Floor((n-1)/2)) mod 3: n in [1..100]]; // G. C. Greubel, Feb 13 2019 CROSSREFS Cf. A039969. Sequence in context: A038555 A138108 A158777 * A179212 A105118 A245359 Adjacent sequences:  A039967 A039968 A039969 * A039971 A039972 A039973 KEYWORD nonn AUTHOR EXTENSIONS More terms from Christian G. Bower, Jun 12 2005 Formula added to the name by Antti Karttunen, Feb 13 2019 STATUS approved

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Last modified September 24 04:42 EDT 2020. Contains 337317 sequences. (Running on oeis4.)