The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation. Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A047266 Numbers that are congruent to {0, 1, 5} mod 6. 5
 0, 1, 5, 6, 7, 11, 12, 13, 17, 18, 19, 23, 24, 25, 29, 30, 31, 35, 36, 37, 41, 42, 43, 47, 48, 49, 53, 54, 55, 59, 60, 61, 65, 66, 67, 71, 72, 73, 77, 78, 79, 83, 84, 85, 89, 90, 91, 95, 96, 97, 101, 102, 103, 107, 108, 109, 113, 114, 115, 119, 120, 121, 125 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS a(n+3) is the Hankel transform of A005773(n+3). - Paul Barry, Nov 04 2008 The numbers m == 0, 2 or 10 mod 12 (the doubles of this sequence, that is, 10, 12, 14, 22, 24, 26, 34, ...) have the property that exactly 1/4 of the 3-part partitions of m form the sides of a triangle. See Stack Exchange, 2013, link. - Ed Pegg Jr, Dec 19 2013 Row sum of a triangle where two rules build the triangle. #1 Start with the value "1" at the top of the triangle. #2 Require every "triple" to contain the values 1,2,3 (see link below). Compare with A136289 that has "3" at the apex. - Craig Knecht, Oct 17 2015 Nonnegative m such that floor(k*m^2/6) = k*floor(m^2/6), where k = 2, 3, 4 or 5. [Bruno Berselli, Dec 03 2015] LINKS Craig Knecht, Triangular row sum of A204259. Index entries for linear recurrences with constant coefficients, signature (1,0,1,-1). FORMULA G.f.: x^2*(1+4*x+x^2) / ((1+x+x^2)*(x-1)^2). - R. J. Mathar, Oct 08 2011 a(n) = 2*(n-1) + A057078(n). - Robert Israel, Dec 01 2014 a(n) = a(n-1) + a(n-3) - a(n-4) for n>4. - Wesley Ivan Hurt, Nov 09 2015 From Wesley Ivan Hurt, Jun 13 2016: (Start) a(n) = 2*n-2+cos(2*n*Pi/3)+sin(2*n*Pi/3)/sqrt(3). a(3k) = 6k-1, a(3k-1) = 6k-5, a(3k-2) = 6k-6. (End) MAPLE seq(seq(6*s+j, j=[0, 1, 5]), s=0..100); # Robert Israel, Dec 01 2014 MATHEMATICA Select[Range[0, 200], Mod[#, 6] == 0 || Mod[#, 6] == 1 || Mod[#, 6] == 5 &] (* Vladimir Joseph Stephan Orlovsky, Jul 07 2011 *) PROG (PARI) concat(0, Vec(x^2*(1+4*x+x^2)/((1+x+x^2)*(x-1)^2) + O(x^100))) \\ Altug Alkan, Oct 17 2015 (MAGMA) [n : n in [0..150] | n mod 6 in [0, 1, 5]]; // Wesley Ivan Hurt, Jun 13 2016 CROSSREFS Cf. A005773, A047240, A047242, A057078, A136289, A204259. Sequence in context: A336857 A049467 A131503 * A026309 A073936 A184811 Adjacent sequences:  A047263 A047264 A047265 * A047267 A047268 A047269 KEYWORD nonn,easy AUTHOR STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified July 23 22:20 EDT 2021. Contains 346265 sequences. (Running on oeis4.)