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.

Showing 1-9 of 9 results.

A096045 a(n) = B(2*n, 2)/B(2*n) (see formula section).

Original entry on oeis.org

1, 10, 46, 190, 766, 3070, 12286, 49150, 196606, 786430, 3145726, 12582910, 50331646, 201326590, 805306366, 3221225470, 12884901886, 51539607550, 206158430206, 824633720830, 3298534883326, 13194139533310, 52776558133246, 211106232532990, 844424930131966
Offset: 0

Views

Author

Benoit Cloitre, Jun 17 2004

Keywords

Crossrefs

Programs

  • Magma
    [3*4^n-2: n in [0..30]]; // Vincenzo Librandi, Aug 13 2011
    
  • Mathematica
    a[n_]:= Sum[2^k*Sum[Binomial[2*n, j]*BernoulliB[j], {j,0,k}], {k,0,2*n}]/BernoulliB[2*n]; Table[a[n], {n, 0, 22}] (* Jean-François Alcover, Jan 14 2015 *)
    NestList[4#+6&,1,30] (* Harvey P. Dale, Dec 27 2016 *)
  • Maxima
    A096045(n):=3*4^n-2$ makelist(A096045(n),n,0,30); /* Martin Ettl, Nov 13 2012 */
    
  • PARI
    a(n)=sum(i=0,2*n,2^i*sum(j=0,i,binomial(2*n,j)*bernfrac(j)))/bernfrac(2*n)
    
  • SageMath
    [3*4^n-2 for n in range(41)] # G. C. Greubel, Jan 22 2023

Formula

a(n) = B(2*n, 2)/B(2*n), where B(n, p) = Sum_{i=0..n} p^i * (Sum_{j=0..i} binomial(n,j)*B(j)) with B(k) = k-th Bernoulli number.
a(n) = 3*4^n - 2.
a(n) = 5*a(n-1) - 4*a(n-2).
a(n) = 4*a(n-1) + 6. First differences give A002063. - Paul Curtz, Jul 07 2008
From G. C. Greubel, Jan 22 2023: (Start)
a(n) = 3*A000302(n) - 2.
G.f.: (1+5*x)/((1-x)*(1-4*x)).
E.g.f.: 3*exp(4*x) - 2*exp(x). (End)

A096046 a(n) = B(2n,3)/B(2n) (see comment).

Original entry on oeis.org

1, 15, 141, 1275, 11481, 103335, 930021, 8370195, 75331761, 677985855, 6101872701, 54916854315, 494251688841, 4448265199575, 40034386796181, 360309481165635, 3242785330490721, 29185067974416495, 262665611769748461
Offset: 0

Views

Author

Benoit Cloitre, Jun 17 2004

Keywords

Comments

B(n,p) = Sum_{i=0..n} p^i*Sum_{j=0..i} binomial(n,j)*B(j) where B(k) = k-th Bernoulli number.

Crossrefs

Programs

  • Magma
    [(1/4)*(7*9^n-3): n in [0..30]]; // Vincenzo Librandi, Aug 13 2011
    
  • Maxima
    A096046(n):=(1/4)*(7*9^n-3)$ makelist(A096046(n),n,0,30); /* Martin Ettl, Nov 13 2012 */
  • PARI
    a(n)=sum(i=0,2*n,3^i*sum(j=0,i,binomial(2*n,j)*bernfrac(j)))/bernfrac(2*n)
    

Formula

a(n) = (1/4)*(7*9^n - 3).
a(n) = 10*a(n-1) - 9*a(n-2); a(0)=1, a(1)=15.
a(n) = 9*a(n-1) + 6. First differences = 14*A001019(n). - Paul Curtz, Jul 07 2008

A096053 a(n) = (3*9^n - 1)/2.

Original entry on oeis.org

1, 13, 121, 1093, 9841, 88573, 797161, 7174453, 64570081, 581130733, 5230176601, 47071589413, 423644304721, 3812798742493, 34315188682441, 308836698141973, 2779530283277761, 25015772549499853, 225141952945498681
Offset: 0

Views

Author

Benoit Cloitre, Jun 18 2004

Keywords

Comments

Generalized NSW numbers. - Paul Barry, May 27 2005
Counts total area under elevated Schroeder paths of length 2n+2, where area under a horizontal step is weighted 3. Case r=4 for family (1+(r-1)x)/(1-2(1+r)x+(1-r)^2*x^2). Case r=2 gives NSW numbers A002315. Fifth binomial transform of (1+8x)/(1-16x^2), A107906. - Paul Barry, May 27 2005
Primes in this sequence include: a(2) = 13, a(4) = 1093, a(7) = 797161. Semiprimes in this sequence include: a(3) = 121 = 11^2, a(5) = 9841 = 13 * 757, a(6) = 88573 = 23 * 3851, a(9) = 64570081 = 1871 * 34511, a(10) = 581130733 = 1597 * 363889, a(12) = 47071589413 = 47 * 1001523179, a(19) = 225141952945498681 = 13097927 * 17189128703.
Sum of divisors of 9^n. - Altug Alkan, Nov 10 2015

Crossrefs

Cf. A107903, A138894 ((5*9^n-1)/4).

Programs

Formula

From Paul Barry, May 27 2005: (Start)
G.f.: (1+3*x)/(1-10*x+9*x^2);
a(n) = Sum_{k=0..n} binomial(2n+1, 2k)*4^k;
a(n) = ((1+sqrt(4))*(5+2*sqrt(4))^n+(1-sqrt(4))*(5-2*sqrt(4))^n)/2. (End)
a(n-1) = (-9^n/3)*B(2n,1/3)/B(2n) where B(n,x) is the n-th Bernoulli polynomial and B(k)=B(k,0) is the k-th Bernoulli number.
a(n) = 10*a(n-1) - 9*a(n-2).
a(n) = 9*a(n-1) + 4. - Vincenzo Librandi, Nov 01 2011
a(n) = A000203(A001019(n)). - Altug Alkan, Nov 10 2015
a(n) = A320030(3^n-1). - Nathan M Epstein, Jan 02 2019

Extensions

Edited by N. J. A. Sloane, at the suggestion of Andrew S. Plewe, Jun 15 2007

A096048 a(n)=B(2n,6)/B(2n) (see comment).

Original entry on oeis.org

1, 42, 1446, 51486, 1848966, 66524910, 2394568086, 86201542014, 3103229527206, 111716029897998, 4021774981740726, 144783880503964062, 5212219528644719046, 187639901505929327406, 6755036440486736068566
Offset: 0

Views

Author

Benoit Cloitre, Jun 17 2004

Keywords

Comments

B(n,p)=sum(i=0,n,p^i*sum(j=0,i,binomial(n,j)*B(j))) where B(k)=k-th Bernoulli number

Crossrefs

Programs

  • Maxima
    a[0]:1$ a[1]:42$ a[2]:1446$ a[3]:51486$ a[n]:=(1/10)*(11*36^n+2*9^n+3*4^n-6)$ A096048(n):=a[n]$ makelist(A096048(n),n,0,30); /* Martin Ettl, Nov 13 2012 */
  • PARI
    a(n)=sum(i=0,2*n,6^i*sum(j=0,i,binomial(2*n,j)*bernfrac(j)))/bernfrac(2*n)
    

Formula

a(n)=(1/10)*(11*36^n+2*9^n+3*4^n-6); a(0)=1, a(1)=42, a(2)=1446, a(3)=51486 and a(n)=50*a(n-1)-553*a(n-2)+1800*a(n-3)-1296*a(n-4)

A096049 a(n) = [B(2n,5)/B(2n)] ( [x] = floor(x), see comment for B(n,k) definition ).

Original entry on oeis.org

1, 31, 745, 18397, 458545, 11455304, 286331664, 7157976493, 178947452208, 4473674081283, 111841775707840, 2796043915880138, 69901094917491465, 1747527354316971026, 43688183741551848165, 1092204592811481165247, 27305114815741345242261, 682627870365123204281633
Offset: 0

Views

Author

Benoit Cloitre, Jun 17 2004

Keywords

Comments

B(n,p) = Sum_{i=0..n} p^i*(Sum_{j=0..i} binomial(n,j)*B(j)) where B(k)=k-th Bernoulli number. B(2n,p)/B(2n) take integer values for all n if p=1,2,3,4,6. p=5 is the smallest integer for which B(2n,5)/B(2n) is not always integer valued.

Crossrefs

Programs

  • PARI
    a(n)=floor(sum(i=0,2*n,5^i*sum(j=0,i,binomial(2*n,j)*bernfrac(j)))/bernfrac(2*n))

Formula

a(n) = floor((1/16)*(21-sqrt(5))*25^n + (1/8)*sqrt(5)*((25/4)^n+(25/9)^n-(25/16)^n) - (1/16)*(5-sqrt(5)) + (1/4)*sqrt(5)*(25/36)^n).

A096054 a(n) = (36^n/6)*B(2n,1/6)/B(2n) where B(n,x) is the n-th Bernoulli polynomial and B(k) = B(k,0) is the k-th Bernoulli number.

Original entry on oeis.org

1, 91, 3751, 138811, 5028751, 181308931, 6529545751, 235085301451, 8463265086751, 304679288612371, 10968470088963751, 394865064451017691, 14215143591303768751, 511745180725868773411, 18422826609078989373751, 663221758853362301815531, 23875983327059668074930751
Offset: 1

Views

Author

Benoit Cloitre, Jun 18 2004

Keywords

Crossrefs

Programs

  • Mathematica
    a[n_] := 6^(2*n-1) * BernoulliB[2*n, 1/6] / BernoulliB[2*n]; Array[a, 15] (* Amiram Eldar, May 07 2025 *)
  • PARI
    a(n)=(1/12)*36^n-(1/6)*9^n-(1/4)*4^n+1/2;

Formula

a(n) = (1/12)*(36^n - 2*9^n - 3*4^n+6).
From Colin Barker, May 30 2020: (Start)
G.f.: x*(1 - 6*x)*(1 + 47*x + 36*x^2) / ((1 - x)*(1 - 4*x)*(1 - 9*x)*(1 - 36*x)).
a(n) = 50*a(n-1) - 553*a(n-2) + 1800*a(n-3) - 1296*a(n-4) for n>4. (End)

A096050 Decimal expansion of lim_{n->oo} B(2n,7)/(B(2n)*49^n) (see comment for B(n,k) definition).

Original entry on oeis.org

1, 0, 6, 2, 7, 5, 1, 6, 9, 9, 6, 9, 0, 2, 1, 1, 0, 7, 8, 2, 4, 5, 8, 3, 2, 5, 1, 9, 3, 3, 2, 6, 2, 6, 6, 9, 8, 2, 2, 7, 9, 5, 4, 2, 1, 1, 5, 1, 7, 2, 6, 6, 3, 1, 5, 7, 7, 2, 4, 0, 8, 4, 2, 6, 8, 1, 7, 1, 9, 1, 0, 5, 7, 9, 2, 3, 9, 1, 8, 7, 8, 5, 9, 0, 4, 0, 0, 9, 5, 8, 2, 1, 1, 2, 2, 3, 5, 7, 7, 1, 3, 8, 8, 8, 2
Offset: 1

Views

Author

Benoit Cloitre, Jun 17 2004

Keywords

Comments

B(n,p) = Sum_{i=0..n} p^i * Sum_{j=0..i} binomial(n,j)*B(j) where B(k) = k-th Bernoulli number. B(2n,p)/B(2n) takes integer values for all n if p=1,2,3,4,6. p=5 is the smallest integer for which B(2n,5)/B(2n) is not always integer-valued. And lim_{n->oo} B(2n,5)/(B(2n)*25^n) = (21-sqrt(5))/16.

Crossrefs

Programs

  • Mathematica
    RealDigits[x/.FindRoot[ 1728x^3-6192x^2+7368x-2911==0,{x,1}, WorkingPrecision-> 120]][[1]] (* Harvey P. Dale, Feb 19 2012 *)
  • PARI
    solve(q=1,1.1,1728*q^3-6192*q^2+7368*q-2911)

Formula

Limit_{n->oo} B(2n, 7)/(B(2n)*49^n) = 1.0627516996902110782... is the smallest root of 1728*X^3 - 6192*X^2 + 7368*X - 2911 = 0.

A096051 Decimal expansion of lim_{n->oo} B(2n,8)/(B(2n)*64^n) (see comment for B(n,k) definition).

Original entry on oeis.org

1, 0, 4, 1, 8, 4, 1, 8, 8, 8, 4, 0, 1, 9, 2, 1, 7, 8, 2, 2, 2, 8, 4, 5, 0, 8, 0, 5, 4, 1, 3, 5, 9, 2, 9, 9, 4, 3, 8, 7, 8, 8, 0, 5, 8, 0, 3, 3, 0, 2, 1, 7, 9, 9, 4, 7, 7, 3, 0, 9, 4, 3, 0, 4, 4, 2, 9, 2, 3, 3, 3, 9, 4, 3, 9, 5, 5, 6, 3, 7, 8, 2, 9, 3, 9, 2, 5, 8, 0, 3, 3, 2, 6, 2, 3, 1, 1, 3, 1, 6, 2, 3, 3, 2, 1
Offset: 1

Views

Author

Benoit Cloitre, Jun 17 2004

Keywords

Comments

B(n,p) = Sum_{i=0..n} (p^i * Sum_{j=0..i} binomial(n,j)*B(j)) where B(k) is the k-th Bernoulli number.

Examples

			1.04184188840192178222845080541359299438788058033021...
		

Crossrefs

Programs

  • Mathematica
    RealDigits[(16 - Sqrt[2])/14, 10, 100][[1]] (* Amiram Eldar, May 08 2022 *)
  • PARI
    (16-sqrt(2))/14

Formula

Equals (16-sqrt(2))/14.

A096052 Decimal expansion of lim_{n->oo} B(2n,5)/(B(2n)*25^n) (see comment for B(n,k) definition).

Original entry on oeis.org

1, 1, 7, 2, 7, 4, 5, 7, 5, 1, 4, 0, 6, 2, 6, 3, 1, 4, 3, 9, 7, 4, 4, 2, 6, 6, 4, 5, 7, 0, 4, 2, 9, 5, 2, 3, 5, 2, 8, 4, 9, 6, 1, 3, 5, 2, 5, 2, 4, 2, 7, 9, 6, 4, 2, 2, 3, 3, 0, 6, 8, 9, 2, 2, 1, 6, 1, 8, 4, 2, 4, 4, 2, 1, 4, 7, 6, 3, 7, 1, 9, 3, 7, 8, 6, 5, 9, 9, 0, 9, 9, 4, 7, 6, 3, 2, 6, 1, 0, 7, 8, 1, 4, 4, 0
Offset: 1

Views

Author

Benoit Cloitre, Jun 17 2004

Keywords

Comments

B(n,p) = Sum_{i=0..n} (p^i * Sum_{j=0..i} binomial(n,j)*B(j)) where B(k) is the k-th Bernoulli number.

Examples

			1.17274575140626314397442664570429523528496135252427...
		

Crossrefs

Programs

  • Mathematica
    RealDigits[(21 - Sqrt[5])/16, 10, 100][[1]] (* Amiram Eldar, May 08 2022 *)
  • PARI
    (21-sqrt(5))/16

Formula

Equals (21-sqrt(5))/16.
Showing 1-9 of 9 results.