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 A090210 Triangle of certain generalized Bell numbers. 11
 1, 1, 1, 2, 1, 1, 5, 7, 1, 1, 15, 87, 34, 1, 1, 52, 1657, 2971, 209, 1, 1, 203, 43833, 513559, 163121, 1546, 1, 1, 877, 1515903, 149670844, 326922081, 12962661, 13327, 1, 1, 4140, 65766991, 66653198353, 1346634725665, 363303011071, 1395857215, 130922, 1, 1 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 COMMENTS Let B_{n}(x) = sum_{j>=0}(exp(j!/(j-n)!*x-1)/j!) and S(n,k) = k! [x^k] taylor(B_{n}(x)), where [x^k] denotes the coefficient of x^k in the Taylor series for B_{n}(x). Then S(n,k) (n>0, k>=0) is the square array representation of the triangle. To illustrate the cross-references of T(n,k) when written as a square array. n\k         A000012,A000012,A002720,A069948,A182925,A182924,... 0: A000012: 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, ... 1: A000110: 1, 1, 2, 5, 15, 52, 203, 877, 4140, ... 2: A020556: 1, 1, 7, 87, 1657, 43833, 1515903, ... 3: A069223: 1, 1, 34, 2971, 513559, 149670844, ... 4: A071379: 1, 1, 209, 163121, 326922081, ... 5: A090209: 1, 1, 1546, 12962661, 363303011071,... 6:  ...     1, 1, 13327, 1395857215, 637056434385865,... Note that the sequence T(0,k) is not included in the data. - Peter Luschny, Mar 27 2011 REFERENCES P. Blasiak, K. A. Penson and A. I. Solomon, The general boson normal ordering problem, Phys. Lett. A 309 (2003) 198-205. M. Schork, On the combinatorics of normal ordering bosonic operators and deforming it, J. Phys. A 36 (2003) 4651-4665. LINKS P. Blasiak, K. A. Penson and A. I. Solomon, The general boson normal ordering problem. W. Lang, First 8 rows. K. A. Penson, P. Blasiak, A. Horzela, A. I. Solomon and G. H. E. Duchamp,Laguerre-type derivatives: Dobinski relations and combinatorial identities, J. Math. Phys. 50, 083512 (2009). FORMULA a(n, m)= Bell(m;n-(m-1)), n>= m-1 >=0, with Bell(m;k) := sum(S2(m;k, p), p=m..m*k), where S2(m;k, p) := (((-1)^p)/p!)*sum(((-1)^r)*binomial(p, r)*fallfac(p, r)^k, r=m..p); with fallfac(n, m) := A008279(n, m) (falling factorials) and m<=p<=k*m, k>=1, m=1, 2, ..., else 0. From eqs.(6) with r=s->m and eq.(19) with S_{r, r}(n, k)-> S2(r;n, k) of the Blasiak et al. reference. a(n, m)= (sum(fallfac(k, m)^(n-(m-1)), k=m..infinity))/exp(1), n>= m-1 >=0, else 0. From eq.(26) with r->m of the Schork reference which is rewritten eq.(11) of the original Blasiak et al. reference. E.g.f. m-th column (no leading zeros): (sum((exp(fallfac(k, m)*x))/k!, k=m..infinity) + A000522(m)/m!)/exp(1). Rewritten from the top of p. 4656 of the Schork reference. EXAMPLE Triangle begins: 1; 1, 1; 2, 1, 1; 5, 7, 1, 1; 15, 87, 34, 1, 1; 52, 1657, 2971, 209, 1, 1; 203, 43833, 513559, 163121, 1546, 1, 1; MAPLE A090210_AsSquareArray := proc(n, k) local r, s, i; if k=0 then 1 else r := [seq(n+1, i=1..k-1)]; s := [seq(1, i=1..k-1)]; exp(-x)*n!^(k-1)*hypergeom(r, s, x); round(evalf(subs(x=1, %), 99)) fi end: seq(lprint(seq(A090210_AsSquareArray(n, k), k=0..6)), n=0..6); # Peter Luschny, Mar 30 2011 MATHEMATICA t[n_, k_] := t[n, k] = Sum[(n+j)!^(k-1)/(j!^k*E), {j, 0, Infinity}]; t[_, 0] = 1; Flatten[ Table[ t[n-k+1, k], {n, 0, 8}, {k, n, 0, -1}]][[1 ;; 43]] (* Jean-François Alcover, Jun 17 2011 *) CROSSREFS Cf. A000110, A020556, A069223, A071379, A090209, A002720, A069948, A182924, A182925, A182933. T(n,n) gives A070227. Sequence in context: A051012 A064644 A306444 * A248925 A168131 A024462 Adjacent sequences:  A090207 A090208 A090209 * A090211 A090212 A090213 KEYWORD nonn,easy,tabl AUTHOR Wolfdieter Lang, Dec 01 2003 STATUS approved

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Last modified February 17 18:14 EST 2020. Contains 332005 sequences. (Running on oeis4.)