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 A093644 (9,1) Pascal triangle. 19
 1, 9, 1, 9, 10, 1, 9, 19, 11, 1, 9, 28, 30, 12, 1, 9, 37, 58, 42, 13, 1, 9, 46, 95, 100, 55, 14, 1, 9, 55, 141, 195, 155, 69, 15, 1, 9, 64, 196, 336, 350, 224, 84, 16, 1, 9, 73, 260, 532, 686, 574, 308, 100, 17, 1, 9, 82, 333, 792, 1218, 1260, 882, 408, 117, 18, 1, 9, 91, 415 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS The array F(9;n,m) gives in the columns m>=1 the figurate numbers based on A017173, including the 11-gonal numbers A051682, (see the W. Lang link). This is the ninth member, d=9, in the family of triangles of figurate numbers, called (d,1) Pascal triangles: A007318 (Pascal), A029653, A093560-5, for d=1..8. This is an example of a Riordan triangle (see A093560 for a comment and A053121 for a comment and the 1991 Shapiro et al. reference on the Riordan group). Therefore the o.g.f. for the row polynomials p(n,x):=sum(a(n,m)*x^m,m=0..n) is G(z,x)=(1+8*z)/(1-(1+x)*z). The SW-NE diagonals give A022099(n-1) = sum( a(n-1-k,k),k=0..ceiling((n-1)/2)), n>=1, with n=0 value 8. Observation by Paul Barry, Apr 29 2004. Proof via recursion relations and comparison of inputs. Triangle T(n,k), read by rows, given by (9,-8,0,0,0,0,0,0,0,...) DELTA (1,0,0,0,0,0,0,0,...) where DELTA is the operator defined in A084938. - Philippe Deléham, Oct 10 2011 REFERENCES Kurt Hawlitschek, Johann Faulhaber 1580-1635, Veroeffentlichung der Stadtbibliothek Ulm, Band 18, Ulm, Germany, 1995, Ch. 2.1.4. Figurierte Zahlen. Ivo Schneider: Johannes Faulhaber 1580-1635, Birkhäuser, Basel, Boston, Berlin, 1993, ch.5, pp. 109-122. LINKS Reinhard Zumkeller, Rows n = 0..125 of triangle, flattened W. Lang, First 10 rows and array of figurate numbers . FORMULA a(n, m)=F(9;n-m, m) for 0<= m <= n, else 0, with F(9;0, 0)=1, F(9;n, 0)=9 if n>=1 and F(9;n, m):=(9*n+m)*binomial(n+m-1, m-1)/m if m>=1. Recursion: a(n, m)=0 if m>n, a(0, 0)= 1; a(n, 0)=9 if n>=1; a(n, m)= a(n-1, m) + a(n-1, m-1). G.f. column m (without leading zeros): (1+8*x)/(1-x)^(m+1), m>=0. T(n, k) = C(n, k) + 8*C(n-1, k) . - Philippe Deléham, Aug 28 2005 Row n : Expansion of (9+x)*((1+x)^(n-1), n>0. - From Philippe Deléham, Oct 10 2011. exp(x) * e.g.f. for row n = e.g.f. for diagonal n. For example, for n = 3 we have exp(x)*(9 + 19*x + 11*x^2/2! + x^3/3!) = 9 + 28*x + 58*x^2/2! + 100*x^3/3! + 155*x^4/4! + .... The same property holds more generally for Riordan arrays of the form ( f(x), x/(1 - x) ). - Peter Bala, Dec 22 2014 G.f.: (-1-8*x)/(-1+x+x*y). - R. J. Mathar, Aug 11 2015 EXAMPLE Triangle begins   [1];   [9,  1];   [9, 10,  1];   [9, 19, 11,  1];   ... PROG (Haskell) a093644 n k = a093644_tabl !! n !! k a093644_row n = a093644_tabl !! n a093644_tabl = [1] : iterate                (\row -> zipWith (+) ([0] ++ row) (row ++ [0])) [9, 1] -- Reinhard Zumkeller, Aug 31 2014 CROSSREFS Row sums: A020714(n-1), n>=1, 1 for n=0, alternating row sums are 1 for n=0, 8 for n=2 and 0 else. The column sequences give for m=1..9: A017173, A051682 (11-gonal), A007586, A051798, A051879, A050405, A052206, A056117, A056003. Cf. A093645 (d=10). Sequence in context: A154220 A133919 A145078 * A164791 A107829 A062357 Adjacent sequences:  A093641 A093642 A093643 * A093645 A093646 A093647 KEYWORD nonn,easy,tabl AUTHOR Wolfdieter Lang, Apr 22 2004 STATUS approved

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Last modified October 15 12:31 EDT 2019. Contains 328026 sequences. (Running on oeis4.)