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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A067109 Number of occurrences of the string n in n! (A000142).

Original entry on oeis.org

1, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 2, 0, 2, 0, 0, 1, 0, 1, 1, 0, 0, 1, 0, 0, 1, 1, 1, 0, 0, 1, 0, 0, 1, 2, 0, 0, 0, 1, 1, 0, 2, 1, 1, 0, 0, 2, 0, 0, 1, 0, 0, 2, 2, 4, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 1, 0, 1, 1, 1, 2, 1, 2, 5, 0
Offset: 1

Views

Author

Amarnath Murthy, Jan 08 2002

Keywords

Comments

a(A033180(n)) > 0. - Reinhard Zumkeller, Aug 23 2008

Examples

			a(4) = 1 as 4! = 24 and 4 occurs once;
a(5) = 0 as 5! = 120 does not contain a 5;
a(20) = 1 as 20! = 2432902008176640000 and 20 occurs once.
		

Crossrefs

Programs

  • Haskell
    import Data.List (tails, isPrefixOf)
    a067109 n = sum $
       map (fromEnum . (show n `isPrefixOf`)) (tails $ show $ a000142 n)
    -- Reinhard Zumkeller, Aug 28 2014
  • Mathematica
    Table[ Length[ StringPosition[ ToString[n! ], ToString[n]]], {n, 1, 75} ]
    Table[SequenceCount[IntegerDigits[n!],IntegerDigits[n],Overlaps->True],{n,100}] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jun 01 2019 *)

Extensions

More terms from Robert G. Wilson v, Jan 09 2002

A082765 Trinomial transform of the factorial numbers (A000142).

Original entry on oeis.org

1, 4, 45, 1282, 70177, 6239016, 817234189, 147950506390, 35370826189857, 10791515504716012, 4091225768720823181, 1886585105032464025674, 1039774852573506696192385, 674970732343624159361034832
Offset: 0

Views

Author

Emanuele Munarini, May 21 2003

Keywords

Comments

Number of ways to use the elements of {1,..,k}, 0<=k<=2n, once each to form a sequence of n (possibly empty) lists, each of length at most 2. - Bob Proctor, Apr 18 2005

Crossrefs

a(n) = Sum[C(n, k)*A099022(k), 0<=k<=n]
Replace "sequence" by "collection" in comment: A105747.
Replace "lists" by "sets" in comment: A003011.

Formula

a(n) = Sum[ Trinomial[n, k] k!, {k, 0, 2n} ] where Trinomial[n, k] = trinomial coefficients (A027907)
Integral_{x=0..infinity} (x^2+x+1)^n*exp(-x) dx - Gerald McGarvey, Oct 14 2006

A089833 a(n) = A000108(n)*(A000142(n+1)-1).

Original entry on oeis.org

0, 1, 10, 115, 1666, 30198, 665148, 17296851, 518916970, 17643220738, 670442556004, 28158587998814, 1295295050441588, 64764752531737100, 3497296636751245560, 202843204931717665155, 12576278705767060962330
Offset: 0

Views

Author

Antti Karttunen, Dec 05 2003

Keywords

Crossrefs

The first column of A089831.

Formula

a(n) = A001813(n) - A000108(n).

A102409 Even triangle n!. This table read by rows gives the coefficients of sum formulas of n-th factorials (A000142). The k-th row (6>=k>=1) contains T(i,k) for i=1 to k+3, where k=[2*n+1+(-1)^(n-1)]/4 and T(i,k) satisfies n! = Sum_{i=1..k+3} T(i,k) * n^(i-1) / (2*k-2)!.

Original entry on oeis.org

0, 1, 0, 0, 0, -20, 8, 0, 0, 20280, -6530, -1275, 362, 3, 0, -8749440, 21627600, -4871940, -66510, 48300, 390, 0, -261763004160, 72965762016, 13117344800, -3757930680, 72406040, 13101144, 90440, 0, -974260634054400, -1140185248443360, 353509119454680, -8136128999880, -3234018579750
Offset: 1

Views

Author

André F. Labossière, Jan 07 2005

Keywords

Comments

Incidentally, the sum of signed coefficients for each k-th row is divisible by (2*k-2)!. Moreover, another variant (but an incomplete one, and sorted differently) of the above sequence is presented in A101751.

Examples

			Triangle starts:
0, 1, 0, 0;
0, -20, 8, 0, 0;
20280, -6530, -1275, 362, 3, 0;
-8749440, 21627600, -4871940, -66510, 48300, 390, 0;
-261763004160, 72965762016, 13117344800, -3757930680, 72406040, 13101144, 90440, 0;
...
11!=39916800; substituting n=11 in the formula of the k-th row we obtain k=6 and the coefficients T(i,6) are those needed for computing 11!.
=> 11! = [ -974260634054400 -1140185248443360*11 +353509119454680*11^2 -8136128999880*11^3 -3234018579750*11^4 +109743298560*11^5 +6053880420*11^6 +34067880*11^7 +9450*11^8 ]/10! = 39916800.
		

Crossrefs

A102410 Odd triangle n!. This table read by rows gives the coefficients of sum formulas of n-th Factorials (A000142). The k-th row (6>=k>=1) contains T(i,k) for i=1 to k+2, where k=[2*n+3+(-1)^n]/4 and T(i,k) satisfies n! = Sum_{i=1..k+2} T(i,k) * n^(i-1) / (2*k-2)!.

Original entry on oeis.org

1, 0, 0, -6, 3, 1, 0, 2400, -2024, 264, 32, 0, 2570400, 909720, -666540, 55800, 3420, 0, -19071521280, 12195884736, -762499920, -282106440, 22425480, 741384, 840, -219303218534400, -11953192930560, 27128332828800, -2808016545600, -125442525600, 14164990560, 280576800
Offset: 1

Views

Author

André F. Labossière, Jan 07 2005

Keywords

Comments

Incidentally, the sum of signed coefficients for each k-th row is divisible by (2*k-2)!.

Examples

			Triangle starts:
1, 0, 0;
-6, 3, 1, 0;
2400, -2024, 264, 32, 0;
2570400, 909720, -666540, 55800, 3420, 0;
-19071521280, 12195884736, -762499920, -282106440, 22425480, 741384, 840;
...
11!=39916800; substituting n=11 in the formula of the k-th row we obtain k=6 and the coefficients T(i,6) are those needed for computing 11!.
=> 11! = [ -219303218534400 -11953192930560*11 +27128332828800*11^2 -2808016545600*11^3 -125442525600*11^4 +14164990560*11^5 +280576800*11^6 +453600*11^7 ]/10! = 39916800.
		

Crossrefs

A121757 Triangle read by rows: multiply Pascal's triangle by 1,2,6,24,120,720,... = A000142.

Original entry on oeis.org

1, 1, 2, 1, 4, 6, 1, 6, 18, 24, 1, 8, 36, 96, 120, 1, 10, 60, 240, 600, 720, 1, 12, 90, 480, 1800, 4320, 5040, 1, 14, 126, 840, 4200, 15120, 35280, 40320, 1, 16, 168, 1344, 8400, 40320, 141120, 322560, 362880, 1, 18, 216, 2016, 15120, 90720, 423360, 1451520
Offset: 0

Views

Author

Alford Arnold, Aug 19 2006

Keywords

Comments

Row sums are 1,3,11,49,261,1631,... = A001339
a(n,k) = D(n+1,k+1) Array D in A253938 is part of a conjectured formula for F(n,p,r) that relates Dyck path peaks and returns. a(n,k) was discovered prior to array D. - Roger Ford, May 19 2016

Examples

			Row 6 is 1*1 5*2 10*6 10*24 5*120 1*720.
From _Vincenzo Librandi_, Dec 16 2012: (Start)
Triangle begins:
1,
1, 2,
1, 4,  6,
1, 6,  18,  24,
1, 8,  36,  96,   120,
1, 10, 60,  240,  600,  720,
1, 12, 90,  480,  1800, 4320,  5040,
1, 14, 126, 840,  4200, 15120, 35280,  40320,
1, 16, 168, 1344, 8400, 40320, 141120, 322560, 362880 etc.
(End)
		

Crossrefs

Cf. A007526 A000522, A005843 (2nd column), A028896 (3rd column).
Cf. A008279.
Cf. A008277, A132159 (mirrored).

Programs

  • Haskell
    a121757 n k = a121757_tabl !! n !! k
    a121757_row n = a121757_tabl !! n
    a121757_tabl = iterate
       (\xs -> zipWith (+) (xs ++ [0]) (zipWith (*) [1..] ([0] ++ xs))) [1]
    -- Reinhard Zumkeller, Mar 06 2014
  • Mathematica
    Flatten[Table[n!(k+1)/(n-k)!,{n,0,10},{k,0,n}]]  (* Harvey P. Dale, Apr 25 2011 *)
  • PARI
    A000142(n)={ return(n!) ; } A007318(n,k)={ return(binomial(n,k)) ; } A121757(n,k)={ return(A007318(n,k)*A000142(k+1)) ; } { for(n=0,12, for(k=0,n, print1(A121757(n,k),",") ; ); ) ; } \\ R. J. Mathar, Sep 02 2006
    

Formula

a(n,k) = A007318(n,k)*A000142(k+1), k=0,1,..,n, n=0,1,2,3... - R. J. Mathar, Sep 02 2006
a(n,k) = A008279(n,k) * (k+1). a(n,k) = n!*(k+1)/(n-k)!. - Franklin T. Adams-Watters, Sep 20 2006

A131980 A coefficient tree from the list partition transform relating A000129, A000142, A000165, A110327, and A110330.

Original entry on oeis.org

1, 2, 6, 2, 24, 24, 120, 240, 24, 720, 2400, 720, 5040, 25200, 15120, 720, 40320, 282240, 282240, 40320, 362880, 3386880, 5080320, 1451520, 40320, 3628800, 43545600, 91445760, 43545600, 3628800, 39916800, 598752000, 1676505600, 1197504000, 199584000, 3628800
Offset: 0

Views

Author

Tom Copeland, Oct 30 2007, Nov 29 2007, Nov 30 2007

Keywords

Comments

Construct the infinite array of polynomials
a(0,t) = 1
a(1,t) = 2
a(2,t) = 6 + 2 t
a(3,t) = 24 + 24 t
a(4,t) = 120 + 240 t + 24 t^2
a(5,t) = 720 + 2400 t + 720 t^2
a(6,t) = 5040 + 25200 t + 15120 t^2 + 720 t^3
This array is the reciprocal array of the following array b(n,t) under the list partition transform and its associated operations described in A133314.
b(0,t) = 1, b(1,t) = -2, b(2,t) = -2*(t-1), b(n,t) = 0 for n>2.
Then A000165(n) = a(n,1).
Lower triangular matrix A110327 = binomial(n,k)*a(n-k,2).
n! * A000129(n+1) = a(n,2) = A110327(n,0).
A110330 = matrix inverse of binomial(n,k)*a(n-k,2) = binomial(n,k)*b(n-k,2).
A000142(n+1) = a(n,0).
From Peter Bala, Sep 09 2013: (Start)
Let {P(n,x)}n>=0 be a polynomial sequence. Koutras has defined generalized Eulerian numbers associated with the sequence P(n,x) as the coefficients A(n,k) in the expansion of P(n,x) in a series of factorials of degree n, namely P(n,x) = Sum_{k=0..n} A(n,k)* binomial(x+n-k,n). The choice P(n,x) = x^n produces the classical Eulerian numbers of A008292. Let now P(n,x) = x*(x + 1)*...*(x + n - 1) denote the n-th rising factorial polynomial. Then the present table is the generalized Eulerian numbers associated with the polynomial sequence P(n,2*x). See A228955 for the generalized Eulerian numbers associated with the polynomial sequence P(n,2*x + 1). (End)

Examples

			Triangle begins as:
        1;
        2;
        6,        2;
       24,       24;
      120,      240,       24;
      720,     2400,      720;
     5040,    25200,    15120,      720;
    40320,   282240,   282240,    40320;
   362880,  3386880,  5080320,  1451520,   40320;
  3628800, 43545600, 91445760, 43545600, 3628800;
		

Crossrefs

Cf. A228955.

Programs

  • GAP
    Flat(List([0..10], n-> List([0..Int(n/2)], k-> Factorial(n)*Binomial(n+1, 2*k+1) ))); # G. C. Greubel, Dec 30 2019
  • Magma
    [Factorial(n)*Binomial(n+1, 2*k+1): k in [0..Floor(n/2)], n in [0..10]]; // G. C. Greubel, Dec 30 2019
    
  • Maple
    for n from 0 to 10 do
    seq( n!*binomial(n+1,2*k+1), k = 0..floor(n/2) )
    end do; # Peter Bala, Sep 09 2013
  • Mathematica
    Table[n!*Binomial[n+1, 2*k+1], {n,0,10}, {k,0,Floor[n/2]}]//Flatten (* G. C. Greubel, Dec 30 2019 *)
  • PARI
    T(n,k) = n!*binomial(n+1, 2*k+1);
    for(n=0,10, for(k=0, n\2, print1(T(n,k), ", "))) \\ G. C. Greubel, Dec 30 2019
    
  • Sage
    [[factorial(n)*binomial(n+1, 2*k+1) for k in (0..floor(n/2))] for n in (0..10)] # G. C. Greubel, Dec 30 2019
    

Formula

E.g.f. for the polynomials b(.,t), introduced above, is 1 - 2x - (t-1) * x^2; therefore e.g.f. for the polynomials a(.,t), which are the row polynomials of this array, is 1 / ( 1 - 2x - (t-1) * x^2 ) = (t-1) / ( t - ( 1 + x*(t-1) )^2 ).
Also, a(n,t) = (1 - t*u^2)^(n+1) (D_u)^n [ 1 / (1 - t*u^2) ] with eval. at u = 1/t. Compare A076743.
a(n,t) = n!*Sum_{k>=0} binomial(n+1,2k+1) * t^k = n!*Sum_{k>=0} A034867(n,k) * t^k.
Additional relations are given by formulas in A133314.
From Peter Bala, Sep 09 2013: (Start)
Recurrence equation: T(n+1,k) = (n+2 +2*k)T(n,k) + (n +2 -2*k)T(n,k-1).
Let P(n,x) = x*(x + 1)*...*(x + n - 1) denote the n-th rising factorial.
T(n,k) = Sum_{j=0..k+1} (-1)^(k+1-j)*binomial(n+1,k+1-j)*P(n,2*j) for n >= 1.
The row polynomial a(n,t) satisfies t*a(n,t)/(1 - t)^(n+1) = Sum_{j>=1} P(n,2*j)*t^j. For example, for n = 3 we have t*(24 + 24*t)/(1 - t)^4 = 2*3*4*t + (4*5*6)*t^2 + (6*7*8)*t^3 + ..., while for n = 4 we have t*(120 + 240*t + 24*t^2)/(1 - t)^5 = (2*3*4*5)*t + (4*5*6*7)*t^2 + (6*7*8*9)*t^3 + .... (End)

Extensions

Removed erroneous and duplicate statements. - Tom Copeland, Dec 03 2013

A280062 a(n) = A049502(A000142(n)).

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 13, 16, 22, 38, 47, 73, 60, 127, 160, 166, 194, 249, 348, 345, 359, 497, 532, 682, 709, 727, 1000, 887, 1312, 1155, 1297, 1934, 2069, 1722, 1796, 2148, 2337, 1839, 2595, 2774, 2440, 3314, 3450, 3253, 3379, 3786, 4466, 4366, 4795, 5189, 5598
Offset: 0

Views

Author

Indranil Ghosh, Jan 04 2017

Keywords

Comments

a(n) is the major index (2nd definition) of n!.

Examples

			for n=15, A000142(n) = 1307674368000 and A049502(1307674368000) = 166. So a(n) = 166.
		

Crossrefs

Programs

  • Python
    import math
    def m(N):
        x=bin(int(N))[2:][::-1]
        s=0
        for i in range(1,len(x)):
            if x[i-1]=="1" and x[i]=="0":
                s+=i
        return s
    a=lambda n: m(math.factorial(n))

A373433 a(n) = A000111(n) * A000142(n). Row sums of A373434.

Original entry on oeis.org

1, 1, 2, 12, 120, 1920, 43920, 1370880, 55843200, 2879815680, 183330604800, 14122244505600, 1294628759424000, 139287595371724800, 17379949655535667200, 2489494639794978816000, 405724534220435189760000, 74646464089618378653696000, 15396938399483145082626048000
Offset: 0

Views

Author

Peter Luschny, Jun 04 2024

Keywords

Crossrefs

Programs

  • Maple
    A373433 := n -> ifelse(n = 0, 1, n! * 2^n * abs(euler(n, 1/2) + euler(n, 1))):
    seq(A373433(n), n = 0..18);
  • Mathematica
    A373433[n_] := 2 I^(n + 1) n! PolyLog[-n, -I]; A373433[0] := 1;
    Table[A373433[n], {n, 0, 18}]
  • SageMath
    # Algorithm of Ludwig Seidel (1877).
    def A373433_list(n) :
        R = []; S = []; A = {-1:0, 0:1}; k = 0; f = 1; e = 1
        for i in (0..n) :
            Am = 0; A[k + e] = 0; e = -e
            for j in (0..i) : Am += A[k]; A[k] = Am; k += e
            R.append(Am); S.append(f*Am); f *= i + 1
        return S
    print(A373433_list(18))

Formula

a(n) = n! * 2^n * |Euler(n, 1/2) + Euler(n, 1)| for n >= 1.
a(n) ~ ((2*n^2)/(Pi*e^2))^n*(8*n + 4/3).

A067067 a(n) = product of nonzero digits of n! (A000142).

Original entry on oeis.org

1, 1, 2, 6, 8, 2, 14, 20, 24, 2304, 2304, 11664, 1512, 2688, 112896, 508032, 18579456, 87091200, 11854080, 368640, 6967296, 22861440, 542126592, 1872809164800, 40633270272, 559872000, 26873856000, 8561413324800, 178362777600
Offset: 0

Views

Author

Amarnath Murthy, Jan 03 2002

Keywords

Examples

			a(10) = 2304 as 10! = 3628800 and 3*6*2*8*8 = 2304.
		

Crossrefs

Programs

  • Mathematica
    f[n_] := Block[{d = Sort[ IntegerDigits[n! ]] }, While[ First[d] == 0, d = Drop[d, 1]]; Return[ Apply[ Times, d]]]; Table[ f[n], {n, 0, 30} ]
    Table[Times@@DeleteCases[IntegerDigits[n!],0],{n,0,30}] (* Harvey P. Dale, Jan 11 2016 *)
  • PARI
    a(n) = {vecprod(select(x->(x!=0), digits(n!)))} \\ Harry J. Smith, May 03 2010

Formula

a(n) = A051801(n!).

Extensions

More terms from Jason Earls, Harvey P. Dale and Robert G. Wilson v, Jan 04 2002
Previous Showing 21-30 of 2943 results. Next