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 A257857 Sequentially filled binary triangle rotated 180 degrees and then superimposed and added to the original triangle. 1
 2, 1, 1, 0, 2, 0, 1, 1, 1, 1, 2, 0, 2, 0, 2, 1, 1, 1, 1, 1, 1, 0, 2, 0, 2, 0, 2, 0, 1, 1, 1, 1, 1, 1, 1, 1, 2, 0, 2, 0, 2, 0, 2, 0, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 0, 2, 0, 2 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The integers in the LINKS illustration hang like ornaments on a tree. LINKS Craig Knecht, Color coded contributions of the individual triangles FORMULA T(n,k)=1 if n even, 1<=k<=n. T(n,k)=2 if n odd and (n+1)/2+k even, 1<=k<=n. T(n,k)=0 if n odd and (n+1)/2+k odd, 1<=k<=n. EXAMPLE Triangle T(n,k) begins:       Row sums 2;                                2 1,  1;                            2 0,  2,  0;                        2 1,  1,  1,  1;                    4 2,  0,  2,  0,  2;                6 1,  1,  1,  1,  1,  1;            6 0,  2,  0,  2,  0,  2,  0;        6 1,  1,  1,  1,  1,  1,  1,  1;    8 MAPLE A257857 := proc(n, k)     if type(n, 'even') then         1 ;     elif type((n+1)/2+k, 'even') then         2 ;     else         0;     end if; end proc: CROSSREFS For row sums for the three other variations of this build process, see A186421, A201629, A240828. Sequence in context: A180997 A143439 A105469 * A339871 A276806 A308427 Adjacent sequences:  A257854 A257855 A257856 * A257858 A257859 A257860 KEYWORD nonn,tabl,easy AUTHOR Craig Knecht, Jul 12 2015 STATUS approved

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Last modified September 28 10:48 EDT 2021. Contains 347714 sequences. (Running on oeis4.)