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A075500 Stirling2 triangle with scaled diagonals (powers of 5). 10

%I

%S 1,5,1,25,15,1,125,175,30,1,625,1875,625,50,1,3125,19375,11250,1625,

%T 75,1,15625,196875,188125,43750,3500,105,1,78125,1984375,3018750,

%U 1063125,131250,6650,140,1,390625,19921875

%N Stirling2 triangle with scaled diagonals (powers of 5).

%C This is a lower triangular infinite matrix of the Jabotinsky type. See the Knuth reference given in A039692 for exponential convolution arrays.

%C The row polynomials p(n,x) := Sum_{m=1..n} a(n,m)x^m, n >= 1, have e.g.f. J(x; z)= exp((exp(5*z) - 1)*x/5) - 1.

%H Andrew Howroyd, <a href="/A075500/b075500.txt">Table of n, a(n) for n = 1..1275</a>

%F a(n, m) = (5^(n-m)) * stirling2(n, m).

%F a(n, m) = (Sum_{p=0..m-1} A075513(m, p)*((p+1)*5)^(n-m))/(m-1)! for n >= m >= 1, else 0.

%F a(n, m) = 5m*a(n-1, m) + a(n-1, m-1), n >= m >= 1, else 0, with a(n, 0) := 0 and a(1, 1)=1.

%F G.f. for m-th column: (x^m)/Product_{k=1..m}(1-5k*x), m >= 1.

%F E.g.f. for m-th column: (((exp(5x)-1)/5)^m)/m!, m >= 1.

%e [1]; [5,1]; [25,15,1]; ...; p(3,x) = x(25 + 15*x + x^2).

%e From _Andrew Howroyd_, Mar 25 2017: (Start)

%e Triangle starts

%e * 1

%e * 5 1

%e * 25 15 1

%e * 125 175 30 1

%e * 625 1875 625 50 1

%e * 3125 19375 11250 1625 75 1

%e * 15625 196875 188125 43750 3500 105 1

%e * 78125 1984375 3018750 1063125 131250 6650 140 1

%e (End)

%p # The function BellMatrix is defined in A264428.

%p # Adds (1,0,0,0, ..) as column 0.

%p BellMatrix(n -> 5^n, 9); # _Peter Luschny_, Jan 28 2016

%t Flatten[Table[5^(n - m) StirlingS2[n, m], {n, 11}, {m, n}]] (* _Indranil Ghosh_, Mar 25 2017 *)

%t BellMatrix[f_Function, len_] := With[{t = Array[f, len, 0]}, Table[BellY[n, k, t], {n, 0, len-1}, {k, 0, len-1}]];

%t rows = 10;

%t M = BellMatrix[5^#&, rows];

%t Table[M[[n, k]], {n, 2, rows}, {k, 2, n}] // Flatten (* _Jean-Fran├žois Alcover_, Jun 23 2018, after _Peter Luschny_ *)

%o (PARI) for(n=1, 11, for(m=1, n, print1(5^(n - m) * stirling(n, m, 2),", ");); print();) \\ _Indranil Ghosh_, Mar 25 2017

%Y Columns 1-7 are A000351, A016164, A075911-A075915. Row sums are A005011(n-1).

%Y Cf. A075499, A075501.

%K nonn,easy,tabl

%O 1,2

%A _Wolfdieter Lang_, Oct 02 2002

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Last modified March 29 01:25 EDT 2020. Contains 333104 sequences. (Running on oeis4.)