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 A014182 Expansion of e.g.f. exp(1-x-exp(-x)). 15
 1, 0, -1, 1, 2, -9, 9, 50, -267, 413, 2180, -17731, 50533, 110176, -1966797, 9938669, -8638718, -278475061, 2540956509, -9816860358, -27172288399, 725503033401, -5592543175252, 15823587507881, 168392610536153, -2848115497132448, 20819319685262839 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,5 COMMENTS E.g.f. A(x) = y satisfies (y + y' + y'') * y - y'^2 = 0. - Michael Somos, Mar 11 2004 The 10-adic sum: B(n) = Sum_{k>=0} k^n*k! simplifies to: B(n) = A014182(n)*B(0) + A014619(n) for n>=0, where B(0) is the 10-adic sum of factorials (A025016); a result independent of base. - Paul D. Hanna, Aug 12 2006 Equals row sums of triangle A143987 and (shifted) = right border of A143987. [Gary W. Adamson, Sep 07 2008] From Gary W. Adamson, Dec 31 2008: (Start) Equals the eigensequence of the inverse of Pascal's triangle, A007318. Binomial transform shifts to the right: (1, 1, 0, -1, 1, 2, -9,...). Double binomial transform = A109747 (End) Convolved with A154107 = A000110, the Bell numbers. [Gary W. Adamson, Jan 04 2009] LINKS Vincenzo Librandi, Table of n, a(n) for n = 0..200 FORMULA E.g.f.: exp(1-x-exp(-x)). a(n) = Sum_{k=0..n} (-1)^(n-k)*Stirling2(n+1,k+1). - Paul D. Hanna, Aug 12 2006 A000587(n+1) = -a(n). - Michael Somos, May 12 2012 G.f.: 1/x/(U(0)-x) -1/x  where U(k)= 1 - x + x*(k+1)/(1 - x/U(k+1)) ; (continued fraction, 2-step). - Sergei N. Gladkovskii, Oct 12 2012 G.f.: 1/(U(0) - x) where U(k) = 1 + x*(k+1)/(1 - x/U(k+1)); (continued fraction, 2-step). - Sergei N. Gladkovskii, Nov 12 2012 G.f.: (G(0) - 1)/(x-1) where G(k) =  1 - 1/(1+k*x+x)/(1-x/(x-1/G(k+1) )); (recursively defined continued fraction). - Sergei N. Gladkovskii, Jan 17 2013 G.f.: G(0)/(1+x)-1 where G(k) = 1 + 1/(1 + k*x - x*(1+k*x)*(1+k*x+x)/(x*(1+k*x+x) + (1+k*x+2*x)/G(k+1) )); (recursively defined continued fraction). - Sergei N. Gladkovskii, Feb 09 2013 G.f.: S-1 where S = sum(k>=0, (2 + x*k)*x^k/prod(i=0..k, (1+x+x*i)) ). - Sergei N. Gladkovskii, Feb 09 2013 G.f.: G(0)*x^2/(1+x)/(1+2*x) + 2/(1+x) - 1 where G(k) =  1 + 2/(x + k*x - x^3*(k+1)*(k+2)/(x^2*(k+2) + 2*(1+k*x+3*x)/G(k+1) )); (recursively defined continued fraction). - Sergei N. Gladkovskii, Feb 09 2013 G.f.: 1/(x*Q(0)) -1/x, where Q(k) = 1 - x/(1 + (k+1)*x/Q(k+1) ); (continued fraction). - Sergei N. Gladkovskii, Sep 27 2013 G.f.: G(0)/(1-x)/x - 1/x, where G(k) = 1 - x^2*(k+1)/(x^2*(k+1) + (x*k + 1 - x)*(x*k + 1)/G(k+1) ); (continued fraction). - Sergei N. Gladkovskii, Feb 06 2014 G.f.:  (1 - Sum_{k>0} k * x^k / ((1 + x) * (1 + 2*x) + ... (1 + k*x))) / (1 - x). - Michael Somos, Nov 07 2014 a(n) = exp(1) * (-1)^n * Sum_{k>=0} (-1)^k * (k + 1)^n / k!. - Ilya Gutkovskiy, Dec 20 2019 EXAMPLE G.f. = 1 - x^2 + x^3 + 2*x^4 - 9*x^5 + 9*x^6 + 50*x^7 - 267*x^8 + 413*x^9 + ... MAPLE a:=series(exp(1-x-exp(-x)), x=0, 27): seq(n!*coeff(a, x, n), n=0..26); # Paolo P. Lava, Mar 26 2019 MATHEMATICA With[{nn=30}, CoefficientList[Series[Exp[1-x-Exp[-x]], {x, 0, nn}], x] Range[0, nn]!]  (* Harvey P. Dale, Jan 15 2012 *) a[ n_] := SeriesCoefficient[ (1 - Sum[ k / Pochhammer[ 1/x + 1, k], {k, n}]) / (1 - x), {x, 0, n} ]; (* Michael Somos, Nov 07 2014 *) PROG (PARI) {a(n)=sum(j=0, n, (-1)^(n-j)*Stirling2(n+1, j+1))} {Stirling2(n, k)=(1/k!)*sum(i=0, k, (-1)^(k-i)*binomial(k, i)*i^n)} \\ Paul D. Hanna, Aug 12 2006 (PARI) {a(n) = if( n<0, 0, n! * polcoeff( exp( 1 - x - exp( -x + x * O(x^n))), n))} /* Michael Somos, Mar 11 2004 */ (Sage) def A014182_list(len):  # len>=1     T = [0]*(len+1); T[1] = 1; R = [1]     for n in (1..len-1):         a, b, c = 1, 0, 0         for k in range(n, -1, -1):             r = a - k*b - (k+1)*c             if k < n : T[k+2] = u;             a, b, c = T[k-1], a, b             u = r         T[1] = u; R.append(u)     return R A014182_list(27)  # Peter Luschny, Nov 01 2012 CROSSREFS Essentially same as A000587. See also A014619. Cf. A025016. Cf. A143987, A109747, A154107, A000110. Sequence in context: A242064 A109322 A000587 * A293037 A131463 A065644 Adjacent sequences:  A014179 A014180 A014181 * A014183 A014184 A014185 KEYWORD sign,easy,nice AUTHOR STATUS approved

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Last modified April 17 23:03 EDT 2021. Contains 343071 sequences. (Running on oeis4.)