cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A000587 Rao Uppuluri-Carpenter numbers (or complementary Bell numbers): e.g.f. = exp(1 - exp(x)).

Original entry on oeis.org

1, -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
Offset: 0

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Author

Keywords

Comments

Alternating row sums of Stirling2 triangle A048993.
Related to the matrix-exponential of the Pascal-matrix, see A000110 and A011971. - Gottfried Helms, Apr 08 2007
Closely linked to A000110 and especially the contribution there of Jonathan R. Love (japanada11(AT)yahoo.ca), Feb 22 2007, by offering what is a complementary finding.
Number of set partitions of 1..n with an even number of parts, minus the number of such partitions with an odd number of parts. - Franklin T. Adams-Watters, May 04 2010
After -2, the smallest prime is a(36) = -1454252568471818731501051, no others through a(100). What is the first prime >0 in the sequence? - Jonathan Vos Post, Feb 02 2011
a(723) ~ 1.9*10^1265 is almost certainly prime. - D. S. McNeil, Feb 02 2011
Stirling transform of a(n) = [1, -1, 0, 1, 1, ...] is A033999(n) = [1, -1, 1, -1, 1, ...]. - Michael Somos, Mar 28 2012
Negated coefficients in the asymptotic expansion: A005165(n)/n! ~ 1 - 1/n + 1/n^2 + 0/n^3 - 1/n^4 - 1/n^5 + 2/n^6 + 9/n^7 + 9/n^8 - 50/n^9 - 267/n^10 - 413/n^11 + O(1/n^12), starting from the O(1/n) term. - Vladimir Reshetnikov, Nov 09 2016
Named after Venkata Ramamohana Rao Uppuluri and John A. Carpenter of the Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee. They are called "Rényi numbers" by Fekete (1999), after the Hungarian mathematician Alfréd Rényi (1921-1970). - Amiram Eldar, Mar 11 2022

Examples

			G.f. = 1 - x + x^3 + x^4 - 2*x^5 - 9*x^6 - 9*x^7 + 50*x^8 + 267*x^9 + 413*x^10 - ...
		

References

  • N. A. Kolokolnikova, Relations between sums of certain special numbers (Russian), in Asymptotic and enumeration problems of combinatorial analysis, pp. 117-124, Krasnojarsk. Gos. Univ., Krasnoyarsk, 1976.
  • Alfréd Rényi, Új modszerek es eredmenyek a kombinatorikus analfzisben. I. MTA III Oszt. Ivozl., Vol. 16 (1966), pp. 7-105.
  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
  • M. V. Subbarao and A. Verma, Some remarks on a product expansion. An unexplored partition function, in Symbolic Computation, Number Theory, Special Functions, Physics and Combinatorics (Gainesville, FL, 1999), pp. 267-283, Kluwer, Dordrecht, 2001.

Crossrefs

Cf. A000110, A011971 (base triangle PE), A078937 (PE^2).

Programs

  • Haskell
    a000587 n = a000587_list !! n
    a000587_list = 1 : f a007318_tabl [1] where
       f (bs:bss) xs = y : f bss (y : xs) where y = - sum (zipWith (*) xs bs)
    -- Reinhard Zumkeller, Mar 04 2014
  • Maple
    b:= proc(n, t) option remember; `if`(n=0, 1-2*t,
          add(b(n-j, 1-t)*binomial(n-1, j-1), j=1..n))
        end:
    a:= n-> b(n, 0):
    seq(a(n), n=0..35);  # Alois P. Heinz, Jun 28 2016
  • Mathematica
    Table[ -1 * Sum[ (-1)^( k + 1) StirlingS2[ n, k ], {k, 0, n} ], {n, 0, 40} ]
    With[{nn=30},CoefficientList[Series[Exp[1-Exp[x]],{x,0,nn}],x] Range[0,nn]!] (* Harvey P. Dale, Nov 04 2011 *)
    a[ n_] := If[ n < 0, 0, n! SeriesCoefficient[ Exp[ 1 - Exp[x]], {x, 0, n}]]; (* Michael Somos, May 27 2014 *)
    a[ n_] := If[ n < 0, 0, With[{m = n + 1}, SeriesCoefficient[ Series[ Nest[ x Factor[ 1 - # /. x -> x / (1 - x)] &, 0, m], {x, 0, m}], {x, 0, m}]]]; (* Michael Somos, May 27 2014 *)
    Table[BellB[n, -1], {n, 0, 20}] (* Vladimir Reshetnikov, Oct 20 2015 *)
    b[1] = 1; k = 1; Flatten[{1, Table[Do[j = k; k -= b[m]; b[m] = j;, {m, 1, n-1}]; b[n] = k; k*(-1)^n, {n, 1, 40}]}] (* Vaclav Kotesovec, Sep 09 2019 *)
  • PARI
    {a(n) = if( n<0, 0, n! * polcoeff( exp( 1 - exp( x + x * O(x^n))), n))}; /* Michael Somos, Mar 14 2011 */
    
  • PARI
    {a(n) = local(A); if( n<0, 0, n++; A = O(x); for( k=1, n, A = x - x * subst(A, x, x / (1 - x))); polcoeff( A, n))}; /* Michael Somos, Mar 14 2011 */
    
  • PARI
    Vec(serlaplace(exp(1 - exp(x+O(x^99))))) /* Joerg Arndt, Apr 01 2011 */
    
  • PARI
    a(n)=round(exp(1)*suminf(k=0,(-1)^k*k^n/k!))
    vector(20,n,a(n-1)) \\ Derek Orr, Sep 19 2014 -- a direct approach
    
  • PARI
    x='x+O('x^66); Vec(serlaplace(exp(1 - exp(x)))) \\ Michel Marcus, Sep 19 2014
    
  • Python
    # The objective of this implementation is efficiency.
    # n -> [a(0), a(1), ..., a(n)] for n > 0.
    def A000587_list(n):
        A = [0 for i in range(n)]
        A[n-1] = 1
        R = [1]
        for j in range(0, n):
            A[n-1-j] = -A[n-1]
            for k in range(n-j, n):
                A[k] += A[k-1]
            R.append(A[n-1])
        return R
    # Peter Luschny, Apr 18 2011
    
  • Python
    # Python 3.2 or higher required
    from itertools import accumulate
    A000587, blist, b = [1,-1], [1], -1
    for _ in range(30):
        blist = list(accumulate([b]+blist))
        b = -blist[-1]
        A000587.append(b) # Chai Wah Wu, Sep 19 2014
    
  • Sage
    expnums(26, -1) # Zerinvary Lajos, May 15 2009
    

Formula

a(n) = e*Sum_{k>=0} (-1)^k*k^n/k!. - Benoit Cloitre, Jan 28 2003
E.g.f.: exp(1 - e^x).
a(n) = Sum_{k=0..n} (-1)^k S2(n, k), where S2(i, j) are the Stirling numbers of second kind A008277.
G.f.: (x/(1-x))*A(x/(1-x)) = 1 - A(x); the binomial transform equals the negative of the sequence shifted one place left. - Paul D. Hanna, Dec 08 2003
With different signs: g.f.: Sum_{k>=0} x^k/Product_{L=1..k} (1 + L*x).
Recurrence: a(n) = -Sum_{i=0..n-1} a(i)*C(n-1, i). - Ralf Stephan, Feb 24 2005
Let P be the lower-triangular Pascal-matrix, PE = exp(P-I) a matrix-exponential in exact integer arithmetic (or PE = lim exp(P)/exp(1) as limit of the exponential); then a(n) = PE^-1 [n,1]. - Gottfried Helms, Apr 08 2007
Take the series 0^n/0! - 1^n/1! + 2^n/2! - 3^n/3! + 4^n/4! + ... If n=0 then the result will be 1/e, where e = 2.718281828... If n=1, the result will be -1/e. If n=2, the result will be 0 (i.e., 0/e). As we continue for higher natural number values of n sequence for the Roa Uppuluri-Carpenter numbers is generated in the numerator, i.e., 1/e, -1/e, 0/e, 1/e, 1/e, -2/e, -9/e, -9/e, 50/e, 267/e, ... . - Peter Collins (pcolins(AT)eircom.net), Jun 04 2007
The sequence (-1)^n*a(n), with general term Sum_{k=0..n} (-1)^(n-k)*S2(n, k), has e.g.f. exp(1-exp(-x)). It also has Hankel transform (-1)^C(n+1,2)*A000178(n) and binomial transform A109747. - Paul Barry, Mar 31 2008
G.f.: 1 / (1 + x / (1 - x / (1 + x / (1 - 2*x / (1 + x / (1 - 3*x / (1 + x / ...))))))). - Michael Somos, May 12 2012
From Sergei N. Gladkovskii, Sep 28 2012 to Feb 07 2014: (Start)
Continued fractions:
G.f.: -1/U(0) where U(k) = x*k - 1 - x + x^2*(k+1)/U(k+1).
G.f.: 1/(U(0)+x) where U(k) = 1 + x - x*(k+1)/(1 + x/U(k+1)).
G.f.: 1+x/G(0) where G(k) = x*k - 1 + x^2*(k+1)/G(k+1).
G.f.: (1 - G(0))/(x+1) where G(k) = 1 - 1/(1-k*x)/(1-x/(x+1/G(k+1) )).
G.f.: 1 + x/(G(0)-x) where G(k) = x*k + 2*x - 1 - x*(x*k+x-1)/G(k+1).
G.f.: G(0)/(1+x), where G(k) = 1-x^2*(k+1)/(x^2*(k+1)+(x*k-1-x)*(x*k-1)/G(k+1)).
(End)
a(n) = B_n(-1), where B_n(x) is n-th Bell polynomial. - Vladimir Reshetnikov, Oct 20 2015
From Mélika Tebni, May 20 2022: (Start)
a(n) = Sum_{k=0..n} (-1)^k*Bell(k)*A129062(n, k).
a(n) = Sum_{k=0..n} (-1)^k*k!*A130191(n, k). (End)

A001861 Expansion of e.g.f. exp(2*(exp(x) - 1)).

Original entry on oeis.org

1, 2, 6, 22, 94, 454, 2430, 14214, 89918, 610182, 4412798, 33827974, 273646526, 2326980998, 20732504062, 192982729350, 1871953992254, 18880288847750, 197601208474238, 2142184050841734, 24016181943732414, 278028611833689478, 3319156078802044158, 40811417293301014150
Offset: 0

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Author

Keywords

Comments

Values of Bell polynomials: ways of placing n labeled balls into n unlabeled (but 2-colored) boxes.
First column of the square of the matrix exp(P)/exp(1) given in A011971. - Gottfried Helms, Mar 30 2007
Base matrix in A011971, second power in A078937, third power in A078938, fourth power in A078939. - Gottfried Helms, Apr 08 2007
Equals row sums of triangle A144061. - Gary W. Adamson, Sep 09 2008
Equals eigensequence of triangle A109128. - Gary W. Adamson, Apr 17 2009
Hankel transform is A108400. - Paul Barry, Apr 29 2009
The number of ways of putting n labeled balls into a set of bags and then putting the bags into 2 labeled boxes. An example is given below. - Peter Bala, Mar 23 2013
The f-vectors of n-dimensional hypercube are given by A038207 = exp[M*B(.,2)] = exp[M*A001861(.)] where M = A238385-I and (B(.,x))^n = B(n,x) are the Bell polynomials (cf. A008277). - Tom Copeland, Apr 17 2014
Moments of the Poisson distribution with mean 2. - Vladimir Reshetnikov, May 17 2016
Exponential self-convolution of Bell numbers (A000110). - Vladimir Reshetnikov, Oct 06 2016

Examples

			a(2) = 6: The six ways of putting 2 balls into bags (denoted by { }) and then into 2 labeled boxes (denoted by [ ]) are
01: [{1,2}] [ ];
02: [ ] [{1,2}];
03: [{1}] [{2}];
04: [{2}] [{1}];
05: [{1} {2}] [ ];
06: [ ] [{1} {2}].
- _Peter Bala_, Mar 23 2013
		

References

  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

For boxes of 1 color, see A000110, for 3 colors see A027710, for 4 colors see A078944, for 5 colors see A144180, for 6 colors see A144223, for 7 colors see A144263, for 8 colors see A221159.
First column of A078937.
Equals 2*A035009(n), n>0.
Row sums of A033306, A036073, A049020, and A144061.

Programs

  • Magma
    [&+[2^k*StirlingSecond(n, k): k in [0..n]]: n in [0..25]]; // Vincenzo Librandi, May 18 2019
  • Maple
    A001861:=n->add(Stirling2(n,k)*2^k, k=0..n); seq(A001861(n), n=0..20); # Wesley Ivan Hurt, Apr 18 2014
    # second Maple program:
    b:= proc(n, m) option remember;
         `if`(n=0, 2^m, m*b(n-1, m)+b(n-1, m+1))
        end:
    a:= n-> b(n, 0):
    seq(a(n), n=0..25);  # Alois P. Heinz, Aug 04 2021
  • Mathematica
    Table[Sum[StirlingS2[n, k]*2^k, {k, 0, n}], {n, 0, 21}] (* Geoffrey Critzer, Oct 06 2009 *)
    mx = 16; p = 1; Range[0, mx]! CoefficientList[ Series[ Exp[ (Exp[p*x] - p - 1)/p + Exp[x]], {x, 0, mx}], x] (* Robert G. Wilson v, Dec 12 2012 *)
    Table[BellB[n, 2], {n, 0, 20}] (* Vaclav Kotesovec, Jan 06 2013 *)
  • PARI
    a(n)=if(n<0,0,n!*polcoeff(exp(2*(exp(x+x*O(x^n))-1)),n))
    
  • PARI
    {a(n)=polcoeff(sum(m=0, n, 2^m*x^m/prod(k=1,m,1-k*x +x*O(x^n))), n)} /* Paul D. Hanna, Feb 15 2012 */
    
  • PARI
    {a(n) = sum(k=0, n, 2^k*stirling(n, k, 2))} \\ Seiichi Manyama, Jul 28 2019
    
  • Sage
    expnums(30, 2) # Zerinvary Lajos, Jun 26 2008
    

Formula

a(n) = Sum_{k=0..n} 2^k*Stirling2(n, k). - Emeric Deutsch, Oct 20 2001
a(n) = exp(-2)*Sum_{k>=1} 2^k*k^n/k!. - Benoit Cloitre, Sep 25 2003
G.f. satisfies 2*(x/(1-x))*A(x/(1-x)) = A(x) - 1; twice the binomial transform equals the sequence shifted one place left. - Paul D. Hanna, Dec 08 2003
PE = exp(matpascal(5)-matid(6)); A = PE^2; a(n)=A[n,1]. - Gottfried Helms, Apr 08 2007
G.f.: 1/(1-2x-2x^2/(1-3x-4x^2/(1-4x-6x^2/(1-5x-8x^2/(1-6x-10x^2/(1-... (continued fraction). - Paul Barry, Apr 29 2009
O.g.f.: Sum_{n>=0} 2^n*x^n / Product_{k=1..n} (1-k*x). - Paul D. Hanna, Feb 15 2012
a(n) ~ exp(-2-n+n/LambertW(n/2))*n^n/LambertW(n/2)^(n+1/2). - Vaclav Kotesovec, Jan 06 2013
G.f.: (G(0) - 1)/(x-1)/2 where G(k) = 1 - 2/(1-k*x)/(1-x/(x-1/G(k+1) )); (continued fraction). - Sergei N. Gladkovskii, Jan 16 2013
G.f.: 1/Q(0) where Q(k) = 1 + x*k - x - x/(1 - 2*x*(k+1)/Q(k+1) ); (continued fraction). - Sergei N. Gladkovskii, Mar 07 2013
G.f.: ((1+x)/Q(0)-1)/(2*x), where Q(k) = 1 - (k+1)*x - 2*(k+1)*x^2/Q(k+1); (continued fraction). - Sergei N. Gladkovskii, May 03 2013
G.f.: T(0)/(1-2*x), where T(k) = 1 - 2*x^2*(k+1)/( 2*x^2*(k+1) - (1-2*x-x*k)*(1-3*x-x*k)/T(k+1) ); (continued fraction). - Sergei N. Gladkovskii, Oct 24 2013
a(n) = Sum_{k=0..n} A033306(n,k) = Sum_{k=0..n} binomial(n,k)*Bell(k)*Bell(n-k), where Bell = A000110 (see Motzkin, p. 170). - Danny Rorabaugh, Oct 18 2015
a(0) = 1 and a(n) = 2 * Sum_{k=0..n-1} binomial(n-1,k)*a(k) for n > 0. - Seiichi Manyama, Sep 25 2017 [corrected by Ilya Gutkovskiy, Jul 12 2020]

A027710 Number of ways of placing n labeled balls into n unlabeled (but 3-colored) boxes.

Original entry on oeis.org

1, 3, 12, 57, 309, 1866, 12351, 88563, 681870, 5597643, 48718569, 447428856, 4318854429, 43666895343, 461101962108, 5072054649573, 57986312752497, 687610920335610, 8442056059773267, 107135148331162767, 1403300026585387686, 18946012544520590991
Offset: 0

Views

Author

George Yuhasz (gyuhasz(AT)vt.edu) and John W. Layman

Keywords

Comments

Binomial transform of this sequence is A078940 and a(n+1) = 3*A078940(n). - Paul D. Hanna, Dec 08 2003
First column of the cube of the matrix exp(P)/exp(1) given in A011971. - Gottfried Helms, Mar 30 2007. Base matrix in A011971, second power in A078937, third power in A078938, fourth power in A078939.
The number of ways of putting n labeled balls into a set of bags and then putting the bags into 3 labeled boxes. - Peter Bala, Mar 23 2013

Crossrefs

Programs

  • Maple
    b:= proc(n, m) option remember; `if`(n=0,
          1, m*b(n-1, m)+3*b(n-1, m+1))
        end:
    a:= n-> b(n, 0):
    seq(a(n), n=0..27);  # Alois P. Heinz, Aug 03 2021
  • Mathematica
    colors=3; Array[ bell, 25 ]; For[ x=1, x<=25, x++, bell[ x ]=0 ]; bell[ 1 ]=colors;
    Print[ "1 ", colors ]; For[ n=2, n<=25, n++, bell[ n ]=colors*bell[ n-1 ];
    For[ i=1, n-i>1, i++, bell[ n-i ]=bell[ n-i ]*(n-i)+colors*bell[ n-i-1 ] ];
    bellsum=0; For[ t=0, tVaclav Kotesovec, Mar 12 2014 *)
  • PARI
    a(n)=if(n<0,0,n!*polcoeff(exp(3*(exp(x+x*O(x^n))-1)),n))
    
  • Sage
    from sage.combinat.expnums import expnums2
    expnums(22, 3) # Zerinvary Lajos, Jun 26 2008

Formula

E.g.f.: exp {3(e^x-1)}. - Michael Somos, Oct 18 2002
a(n) = exp(-3)*Sum_{k>=0} 3^k*k^n/k!. - Benoit Cloitre, Sep 25 2003
G.f.: 3*(x/(1-x))*A(x/(1-x)) = A(x) - 1; thrice the binomial transform equals the sequence shifted one place left. - Paul D. Hanna, Dec 08 2003
a(n) = Sum_{k = 0..n} 3^k*A048993(n, k); A048993: Stirling2 numbers. - Philippe Deléham, May 09 2004
PE=exp(matpascal(5))/exp(1); A = PE^3; a(n)= A[ n,1 ] with exact integer arithmetic: PE=exp(matpascal(5)-matid(6)); A = PE^3; a(n)=A[ n,1]. - Gottfried Helms, Apr 08 2007
G.f.: (G(0) - 1)/(x-1)/3 where G(k) = 1 - 3/(1-k*x)/(1-x/(x-1/G(k+1) )); (recursively defined continued fraction). - Sergei N. Gladkovskii, Jan 16 2013
G.f.: T(0)/(1-3*x), where T(k) = 1 - 3*x^2*(k+1)/( 3*x^2*(k+1) - (1-3*x-x*k)*(1-4*x-x*k)/T(k+1) ); (continued fraction). - Sergei N. Gladkovskii, Oct 24 2013
a(n) ~ n^n * exp(n/LambertW(n/3)-3-n) / (sqrt(1+LambertW(n/3)) * LambertW(n/3)^n). - Vaclav Kotesovec, Mar 12 2014
G.f.: Sum_{j>=0} 3^j*x^j / Product_{k=1..j} (1 - k*x). - Ilya Gutkovskiy, Apr 07 2019

Extensions

Entry revised by N. J. A. Sloane, Apr 25 2007

A078944 First column of A078939, the fourth power of lower triangular matrix A056857.

Original entry on oeis.org

1, 4, 20, 116, 756, 5428, 42356, 355636, 3188340, 30333492, 304716148, 3218555700, 35618229364, 411717043252, 4957730174836, 62045057731892, 805323357485684, 10820999695801908, 150271018666120564, 2153476417340487476
Offset: 0

Views

Author

Paul D. Hanna, Dec 18 2002

Keywords

Comments

Also, the number of ways of placing n labeled balls into n unlabeled (but 4-colored) boxes. Binomial transform of this sequence is A078945 and a(n+1) = 4*A078945(n). - Paul D. Hanna, Dec 08 2003
First column of PE^4, where PE is given in A011971, second power in A078937, third power in A078938, fourth power in A078939. - Gottfried Helms, Apr 08 2007
The number of ways of putting n labeled balls into a set of bags and then putting the bags into 4 labeled boxes. - Peter Bala, Mar 23 2013
Exponential self-convolution of A001861. - Vladimir Reshetnikov, Oct 06 2016

Crossrefs

Programs

  • Maple
    A056857 := proc(n,c) combinat[bell](n-1-c)*binomial(n-1,c) ; end: A078937 := proc(n,c) add( A056857(n,k)*A056857(k+1,c),k=0..n) ; end: A078938 := proc(n,c) add( A078937(n,k)*A056857(k+1,c),k=0..n) ; end: A078939 := proc(n,c) add( A078938(n,k)*A056857(k+1,c),k=0..n) ; end: A078944 := proc(n) A078939(n+1,0) ; end: seq(A078944(n),n=0..25) ; # R. J. Mathar, May 30 2008
    # second Maple program:
    b:= proc(n, m) option remember; `if`(n=0, 4^m,
          add(b(n-1, max(m, j)), j=1..m+1))
        end:
    a:= n-> b(n, 0):
    seq(a(n), n=0..25);  # Alois P. Heinz, Aug 03 2021
  • Mathematica
    Table[n!, {n, 0, 20}]CoefficientList[Series[E^(4E^x-4), {x, 0, 20}], x]
    Table[BellB[n,4],{n,0,20}] (* Vaclav Kotesovec, Mar 12 2014 *)
    With[{nn=20},CoefficientList[Series[Exp[4(Exp[x]-1)],{x,0,nn}],x] Range[0,nn]!] (* Harvey P. Dale, May 03 2022 *)
  • Sage
    expnums(20, 4) # Zerinvary Lajos, Jun 26 2008

Formula

PE=exp(matpascal(5))/exp(1); A = PE^4; a(n)= A[ n,1 ] with exact integer arithmetic: PE=exp(matpascal(5)-matid(6)); A = PE^4; a(n)=A[ n,1]. - Gottfried Helms, Apr 08 2007
E.g.f.: exp(4*(exp(x)-1)).
a(n) = exp(-4)*Sum_{k>=0} 4^k*k^n/k!. - Benoit Cloitre, Sep 25 2003
G.f.: 4*(x/(1-x))*A(x/(1-x)) = A(x) - 1; four times the binomial transform equals this sequence shifted one place left. - Paul D. Hanna, Dec 08 2003
a(n) = Sum_{k = 0..n} 4^k*A048993(n, k); A048993: Stirling2 numbers. - Philippe Deléham, May 09 2004
G.f.: (G(0) - 1)/(x-1)/4 where G(k) = 1 - 4/(1-k*x)/(1-x/(x-1/G(k+1))); (recursively defined continued fraction). - Sergei N. Gladkovskii, Jan 16 2013
G.f.: T(0)/(1-4*x), where T(k) = 1 - 4*x^2*(k+1)/(4*x^2*(k+1) - (1-(k+4)*x)*(1-(k+5)*x)/T(k+1)); (continued fraction). - Sergei N. Gladkovskii, Oct 28 2013
a(n) ~ n^n * exp(n/LambertW(n/4)-4-n) / (sqrt(1+LambertW(n/4)) * LambertW(n/4)^n). - Vaclav Kotesovec, Mar 12 2014
G.f.: Sum_{j>=0} 4^j*x^j / Product_{k=1..j} (1 - k*x). - Ilya Gutkovskiy, Apr 07 2019

Extensions

More terms from R. J. Mathar, May 30 2008
Edited by N. J. A. Sloane, Jul 02 2008 at the suggestion of R. J. Mathar

A078938 Cube of lower triangular matrix of A056857 (successive equalities in set partitions of n).

Original entry on oeis.org

1, 3, 1, 12, 6, 1, 57, 36, 9, 1, 309, 228, 72, 12, 1, 1866, 1545, 570, 120, 15, 1, 12351, 11196, 4635, 1140, 180, 18, 1, 88563, 86457, 39186, 10815, 1995, 252, 21, 1, 681870, 708504, 345828, 104496, 21630, 3192, 336, 24, 1, 5597643, 6136830, 3188268
Offset: 0

Views

Author

Paul D. Hanna, Dec 18 2002

Keywords

Comments

Cube of the matrix exp(P)/exp(1) given in A011971. - Gottfried Helms, Apr 08 2007. Base matrix in A011971, second power in A129321, third power in this entry, fourth power in A078939
First column gives A027710. Row sums give A078940.
Riordan array [exp(3*exp(x)-3),x], whose production matrix has e.g.f. exp(x*t)(t+3*exp(x)). [From Paul Barry, Nov 26 2008]

Examples

			Rows:
1,
3,1,
12,6,1,
57,36,9,1,
309,228,72,12,1,
1866,1545,570,120,15,1,
12351,11196,4635,1140,180,18,1,
...
		

Crossrefs

Programs

  • PARI
    m=matpascal(5)-matid(6); pe=matid(6)+m/1! + m^2/2!+m^3/3!+m^4/4!+m^5/5! ; A = pe^3 - Gottfried Helms, Apr 08 2007

Formula

PE=exp(matpascal(5))/exp(1); A = PE^3; a(n)= A[ n,sequentially read ] with exact integer arithmetic: PE=exp(matpascal(5)-matid(6)); A = PE^3; a(n)=A[ n,sequentially read] - Gottfried Helms, Apr 08 2007
Exponential function of 3*Pascal's triangle (taken as a lower triangular matrix) divided by e^3: [A078938] = (1/e^3)*exp(3*[A007318]) = [A056857]^3.

Extensions

Entry revised by N. J. A. Sloane, Apr 25 2007

A078939 Fourth power of lower triangular matrix of A056857 (successive equalities in set partitions of n).

Original entry on oeis.org

1, 4, 1, 20, 8, 1, 116, 60, 12, 1, 756, 464, 120, 16, 1, 5428, 3780, 1160, 200, 20, 1, 42356, 32568, 11340, 2320, 300, 24, 1, 355636, 296492, 113988, 26460, 4060, 420, 28, 1, 3188340, 2845088, 1185968, 303968, 52920, 6496, 560, 32, 1, 30333492, 28695060
Offset: 0

Views

Author

Paul D. Hanna, Dec 18 2002

Keywords

Comments

First column gives A078944. Row sums are given by A078945.

Examples

			Rows: {1}, {4,1}, {20,8,1}, {116,60,12,1}, {756,464,120,16,1}, ...
		

Crossrefs

Formula

Exponential function of 4*Pascal's triangle (taken as a lower triangular matrix) divided by e^4: [A078939] = (1/e^4)*exp(4*[A007318]) = [A056857]^4.

A129323 Second column of PE^2.

Original entry on oeis.org

0, 1, 4, 18, 88, 470, 2724, 17010, 113712, 809262, 6101820, 48540778, 405935688, 3557404838, 32577733972, 310987560930, 3087723669600, 31823217868318, 339845199259500, 3754422961010522, 42843681016834680, 504339820818380694
Offset: 0

Views

Author

Gottfried Helms, Apr 08 2007

Keywords

Comments

Base matrix is in A011971; second power is in A078937; third power is in A078938; fourth power is in A078939.

Crossrefs

Programs

Formula

PE=exp(matpascal(5))/exp(1); A = PE^2; a(n)=A[n,2] with exact integer arithmetic: PE=exp(matpascal(5)-matid(6)); A = PE^2; a(n)=A[n,2]

Extensions

More terms from R. J. Mathar, May 30 2008

A129324 Third column of PE^2.

Original entry on oeis.org

0, 0, 1, 6, 36, 220, 1410, 9534, 68040, 511704, 4046310, 33560010, 291244668, 2638581972, 24901833866, 244333004790, 2487900487440, 26245651191600, 286408960814862, 3228529392965250, 37544229610105220, 449858650676764140
Offset: 0

Views

Author

Gottfried Helms, Apr 08 2007

Keywords

Comments

Base matrix is in A011971; second power is in A078937; third power is in A078938; fourth power is in A078939.

Crossrefs

Programs

Formula

PE=exp(matpascal(5))/exp(1); A = PE^2; a(n)=A[n,3]; with exact integer arithmetic: PE=exp(matpascal(5)-matid(6)); A = PE^2; a(n)=A[n,3].
E.g.f.: (x^2/2) * exp(2 * (exp(x) - 1)). - Ilya Gutkovskiy, Jul 11 2020

Extensions

More terms from R. J. Mathar, May 30 2008

A129325 Fourth column of PE^2.

Original entry on oeis.org

0, 0, 0, 1, 8, 60, 440, 3290, 25424, 204120, 1705680, 14836470, 134240040, 1262060228, 12313382536, 124509169330, 1303109358880, 14098102762160, 157473907149600, 1813923418494126, 21523529286435000, 262809607270736540
Offset: 0

Views

Author

Gottfried Helms, Apr 08 2007

Keywords

Comments

Base matrix is in A011971; second power is in A078937; third power is in A078938; fourth power is in A078939.

Crossrefs

Programs

Formula

PE=exp(matpascal(5))/exp(1); A = PE^2; a(n)=A[n,4] with exact integer arithmetic: PE=exp(matpascal(5)-matid(6)); A = PE^2; a(n)=A[n,4]

Extensions

More terms from R. J. Mathar and Herman Jamke (hermanjamke(AT)fastmail.fm), May 01 2008

A129327 Second column of PE^3.

Original entry on oeis.org

0, 1, 6, 36, 228, 1545, 11196, 86457, 708504, 6136830, 55976430, 535904259, 5369146272, 56145107577, 611336534802, 6916529431620, 81152874393168, 985767316792449, 12376996566040980, 160399065135692073
Offset: 0

Views

Author

Gottfried Helms, Apr 08 2007

Keywords

Comments

Base matrix is in A011971; second power is in A078937; third power is in A078938; fourth power is in A078939.

Crossrefs

Programs

Formula

PE=exp(matpascal(5))/exp(1); A = PE^3; a(n)= A[ n,2 ] with exact integer arithmetic: PE=exp(matpascal(5)-matid(6)); A = PE^3; a(n)=A[ n,2]

Extensions

More terms from R. J. Mathar, May 30 2008
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