This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A131406 3*A128174 - 2*A000012(signed). 0
 1, 2, 1, 1, 2, 1, 2, 1, 2, 1, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Row sums = A032766, congruent to {0,1} mod 3: (1, 3, 4, 6, 7, 9, 10,...). Sequence array for the expansion of (1+2x)/(1-x^2). A105476 is an eigensequence. [From Paul Barry, Nov 03 2010] LINKS FORMULA 3*A128174 - 2*A000012(signed + - + 1 by columns). (1, 2, 1, 2, 1,...) in every column. Triangle T(n,k)=if(k<=n,(3-(-1)^(n-k))/2). [From Paul Barry, Nov 03 2010] EXAMPLE First few rows of the triangle are: 1; 2, 1; 1, 2, 1; 2, 1, 2, 1; 1, 2, 1, 2, 1; 2, 1, 2, 1, 2, 1; ... MATHEMATICA T[n_, k_] := Mod[n-k, 2]+1; Table[T[n, k], {n, 1, 10}, {k, 1, n}] // Flatten (* Jean-François Alcover, Nov 17 2016 *) CROSSREFS Cf. A128174, A000012, A032766. Sequence in context: A001030 A246140 A071709 * A029440 A061337 A253051 Adjacent sequences:  A131403 A131404 A131405 * A131407 A131408 A131409 KEYWORD nonn,tabl AUTHOR Gary W. Adamson, Jul 07 2007 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 October 21 20:44 EDT 2019. Contains 328315 sequences. (Running on oeis4.)