A005995 Alkane (or paraffin) numbers l(8,n).
1, 3, 12, 28, 66, 126, 236, 396, 651, 1001, 1512, 2184, 3108, 4284, 5832, 7752, 10197, 13167, 16852, 21252, 26598, 32890, 40404, 49140, 59423, 71253, 85008, 100688, 118728, 139128, 162384, 188496, 218025, 250971, 287964, 329004, 374794, 425334, 481404, 543004
Offset: 0
A053127 Binomial coefficients C(2*n-4,5).
6, 56, 252, 792, 2002, 4368, 8568, 15504, 26334, 42504, 65780, 98280, 142506, 201376, 278256, 376992, 501942, 658008, 850668, 1086008, 1370754, 1712304, 2118760, 2598960, 3162510, 3819816, 4582116, 5461512, 6471002, 7624512
Offset: 5
References
- M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, 1964 (and various reprintings).
Links
- Vincenzo Librandi, Table of n, a(n) for n = 5..200
- M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards, Applied Math. Series 55, Tenth Printing, 1972 [alternative scanned copy].
- Milan Janjic, Two Enumerative Functions, University of Banja Luka (Bosnia and Herzegovina, 2017).
- Ângela Mestre and José Agapito, Square Matrices Generated by Sequences of Riordan Arrays, J. Int. Seq., Vol. 22 (2019), Article 19.8.4.
- Index entries for sequences related to Chebyshev polynomials.
- Index entries for linear recurrences with constant coefficients, signature (6,-15,20,-15,6,-1).
Programs
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Haskell
a053127 = (* 2) . a053132 -- Reinhard Zumkeller, Mar 03 2015
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Magma
[Binomial(2*n-4,5): n in [5..40]]; // Vincenzo Librandi, Oct 07 2011
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Mathematica
Binomial[2Range[5,40]-4,5] (* or *) LinearRecurrence[{6,-15,20,-15,6,-1},{6,56,252,792,2002,4368},30] (* Harvey P. Dale, Jun 03 2013 *)
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PARI
for(n=5,50, print1(binomial(2*n-4,5), ", ")) \\ G. C. Greubel, Aug 26 2018
Formula
a(n) = binomial(2*n-4, 5) if n >= 5 else 0.
a(n) = -A053123(n,5), n >= 5; a(n) := 0, n=0..4 (sixth column of shifted Chebyshev's S-triangle, decreasing order).
G.f.: (6+20*x+6*x^2)/(1-x)^6.
a(n) = 6*a(n-1) - 15*a(n-2) +20*a(n-3) -15*a(n-4) +6*a(n-5) -a(n-6). - Harvey P. Dale, Jun 03 2013
E.g.f.: (-840 + 750*x - 330*x^2 + 95*x^3 - 20*x^4 + 4*x^5)*exp(x)/15. - G. C. Greubel, Aug 26 2018
a(n) = (2*n-8)*(2*n-7)*(2*n-6)*(2*n-5)*(2*n-4)/120. - Wesley Ivan Hurt, Mar 25 2020
From Amiram Eldar, Jan 03 2022: (Start)
Sum_{n>=5} 1/a(n) = 335/12 - 40*log(2).
Sum_{n>=5} (-1)^(n+1)/a(n) = 85/12 - 10*log(2). (End)
A060082 Coefficients of even-indexed Euler polynomials (falling powers without zeros).
1, 1, -1, 1, -2, 1, 1, -3, 5, -3, 1, -4, 14, -28, 17, 1, -5, 30, -126, 255, -155, 1, -6, 55, -396, 1683, -3410, 2073, 1, -7, 91, -1001, 7293, -31031, 62881, -38227, 1, -8, 140, -2184, 24310, -177320, 754572, -1529080, 929569, 1, -9, 204, -4284, 67626, -753610, 5497596, -23394924, 47408019
Offset: 0
Comments
E(2n,x) = x^(2n) + Sum_{k=1..n} a(n,k)*x^(2n-2k+1).
Examples
E(0,x) = 1. E(2,x) = x^2 - x. E(4,x) = x^4 - 2*x^3 + x. E(6,x) = x^6 - 3*x^5 + 5*x^3 - 3*x. E(8,x) = x^8 - 4*x^7 + 14*x^5 - 28*x^3 + 17*x. E(10,x) = x^10 - 5*x^9 + 30*x^7 - 126*x^5 + 255*x^3 - 155*x.
References
- M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, 1964 (and various reprintings), p. 809.
Links
- Vincenzo Librandi, Table of n, a(n) for n = 0..1000
- M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards, Applied Math. Series 55, Tenth Printing, 1972 [alternative scanned copy].
- Z.-W. Sun, Introduction to Bernoulli and Euler polynomials
Crossrefs
E(2n, 1/2)*(-4)^n = A000364(n) (signless Euler numbers without zeros).
Programs
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Mathematica
Table[ CoefficientList[ EulerE[2*n, x], x] // Reverse // DeleteCases[#, 0]&, {n, 0, 9}] // Flatten (* Jean-François Alcover, Jun 21 2013 *)
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PARI
{B(n,v='x)=sum(i=0,n,binomial(n,i)*bernfrac(i)*v^(n-i))} E(n,v='x)=2/(n+1)*(B(n+1,v)-2^(n+1)*B(n+1,v/2)) \\ Ralf Stephan, Nov 05 2004
Formula
E(n, x) = 2/(n+1) * [B(n+1, x) - 2^(n+1)*B(n+1, x/2) ], with B(n, x) the Bernoulli polynomials.
Extensions
Edited by Ralf Stephan, Nov 05 2004
A091036 Sixth column (k=7) of array A090438 ((4,2)-Stirling2) divided by 48=4!*2.
1, 840, 498960, 285405120, 173145772800, 115598414131200, 86165279456256000, 72034173625430016000, 67538393730337001472000, 70856069211827240140800000, 82901600977837870964736000000
Offset: 4
Programs
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Maple
A091036 := proc(n) binomial(2*n-2,5)*(2*n)!/7!/4!/2 ; end proc: seq(A091036(n),n=4..40) ; # R. J. Mathar, Jul 27 2022
Formula
a(n)=A090438(n, 7)/48, n>=4.
a(n)=binomial(2*n-2, 5)*(2*n)!/(7!*4!*2)= A053132(n+1)*(2*n)!/(7!*4!), n>=4.
E.g.f.:(sum(((-1)^(p+1))*binomial(7, p)*hypergeom([(p-1)/2, p/2], [], 4*x), p=2..7) + 6)/(7!*48) (cf. A090438).
D-finite with recurrence (2*n-7)*(n-4)*a(n) -2*n*(n-1)*(2*n-1)*(2*n-3)*a(n-1)=0. - R. J. Mathar, Jul 27 2022
A196790 Binomial coefficients C(2*n-9,10).
11, 286, 3003, 19448, 92378, 352716, 1144066, 3268760, 8436285, 20030010, 44352165, 92561040, 183579396, 348330136, 635745396, 1121099408, 1917334783, 3190187286, 5178066751, 8217822536, 12777711870, 19499099620, 29248649430, 43183019880, 62828356305, 90177170226
Offset: 10
Links
- Vincenzo Librandi, Table of n, a(n) for n = 10..200
Programs
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Magma
[Binomial(2*n-9,10): n in [10..40]];
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Mathematica
a[n_] := Binomial[2*n - 9, 10]; Array[a, 20, 10] (* Amiram Eldar, Oct 21 2022 *)
Formula
G.f.: x^10*(11+165*x+462*x^2+330*x^3+55*x^4+x^5) / (1-x)^11. - R. J. Mathar, Oct 08 2011
From Amiram Eldar, Oct 21 2022: (Start)
Sum_{n>=10} 1/a(n) = 447187/252 - 2560*log(2).
Sum_{n>=10} (-1)^n/a(n) = 40*Pi + 80*log(2) - 6517/36. (End)
Comments
References
Links
Crossrefs
Programs
Maple
Mathematica
PARI
Formula