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 A162515 Triangle of coefficients of polynomials defined by Binet form: P(n,x) = (U^n - L^n)/d, where U = (x + d)/2, L = (x - d)/2, d = sqrt(x^2 + 4). 6
 0, 1, 1, 0, 1, 0, 1, 1, 0, 2, 0, 1, 0, 3, 0, 1, 1, 0, 4, 0, 3, 0, 1, 0, 5, 0, 6, 0, 1, 1, 0, 6, 0, 10, 0, 4, 0, 1, 0, 7, 0, 15, 0, 10, 0, 1, 1, 0, 8, 0, 21, 0, 20, 0, 5, 0, 1, 0, 9, 0, 28, 0, 35, 0, 15, 0, 1, 1, 0, 10, 0, 36, 0, 56, 0, 35, 0, 6, 0, 1, 0, 11, 0, 45, 0, 84, 0, 70, 0, 21, 0, 1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,10 COMMENTS Row sums 0,1,1,2,3,5,... are the Fibonacci numbers, A000045. Note that the coefficients are given in decreasing order. - M. F. Hasler, Dec 07 2011 Essentially a mirror image of A168561. - Philippe Deléham, Dec 08 2013 LINKS G. C. Greubel, Rows n = 0..101 of triangle T. Copeland, Addendum to Elliptic Lie Triad FORMULA P(n,x) = x*P(n-1, x) + P(n-2, x), where P(0,x)=0 and P(1,x)=1. T(n,k) = T(n-1, k) + T(n-2, k-2) for n>=2. - Philippe Deléham, Dec 08 2013 EXAMPLE Polynomial expansion:   0;   1;   x;   x^2 + 1;   x^3 + 2*x;   x^4 + 3*x^2 + 1; First rows:   0;   1;   1, 0;   1, 0, 1;   1, 0, 2, 0;   1, 0, 3, 0, 1;   1, 0, 4, 0, 3, 0; Row 6 matches P(6,x)=x^5 + 4*x^3 + 3*x. MAPLE 0, seq(seq(`if`(`mod`(k, 2)=0, binomial(n-k/2, k/2), 0), k = 0..n), n = 0..15); # G. C. Greubel, Jan 01 2020 MATHEMATICA Join[{0}, Table[If[EvenQ[k], Binomial[n-k/2, k/2], 0], {n, 0, 15}, {k, 0, n} ]//Flatten] (* G. C. Greubel, Jan 01 2020 *) PROG (PARI) P(n) =  my( d=(4 + x^2)^(1/2), U=(x+d)/2, L=(x-d)/2); Vec(Pol((U^n-L^n)/d))  \\ M. F. Hasler, Dec 07 2011 (MAGMA) function T(n, k)   if (k mod 2) eq 0 then return Round( Gamma(n-k/2+1)/(Gamma(k/2+1)*Gamma(n-k+1)));   else return 0;   end if; return T; end function; [0] cat [T(n, k): k in [0..n], n in [0..15]]; // G. C. Greubel, Jan 01 2020 (Sage) @CachedFunction def T(n, k):     if (k%2==0): return binomial(n-k/2, k/2)     else: return 0 [0]+flatten([[T(n, k) for k in (0..n)] for n in (0..15)]) # G. C. Greubel, Jan 01 2020 (GAP) T:= function(n, k)     if (k mod 2)=0 then return Binomial(n- k/2, k/2);     else return 0;     fi; end; Concatenation([0], Flat(List([0..15], n-> List([0..n], k-> T(n, k) ))) ); # G. C. Greubel, Jan 01 2020 CROSSREFS Cf. A000045, A049310, A053119, A162514, A162516, A162517. Sequence in context: A083280 A060689 A053119 * A175267 A108045 A298972 Adjacent sequences:  A162512 A162513 A162514 * A162516 A162517 A162518 KEYWORD nonn,tabf AUTHOR Clark Kimberling, Jul 05 2009 STATUS approved

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Last modified April 14 07:59 EDT 2021. Contains 342946 sequences. (Running on oeis4.)