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 1-10 of 10 results.

A306680 Square array A(n,k), n >= 0, k >= 0, read by antidiagonals, where column k is the expansion of g.f. ((1-x)^(k-1))/((1-x)^k-x^(k+1)).

Original entry on oeis.org

1, 1, 2, 1, 1, 3, 1, 1, 2, 4, 1, 1, 1, 3, 5, 1, 1, 1, 2, 5, 6, 1, 1, 1, 1, 4, 8, 7, 1, 1, 1, 1, 2, 7, 13, 8, 1, 1, 1, 1, 1, 5, 12, 21, 9, 1, 1, 1, 1, 1, 2, 11, 21, 34, 10, 1, 1, 1, 1, 1, 1, 6, 21, 37, 55, 11, 1, 1, 1, 1, 1, 1, 2, 16, 37, 65, 89, 12
Offset: 0

Views

Author

Seiichi Manyama, Mar 05 2019

Keywords

Examples

			A(4,1) = A306713(4,1) = 5, A(4,2) = A306713(8,2) = 4.
Square array begins:
   1,  1,  1,  1,  1,  1, 1, 1, 1, ...
   2,  1,  1,  1,  1,  1, 1, 1, 1, ...
   3,  2,  1,  1,  1,  1, 1, 1, 1, ...
   4,  3,  2,  1,  1,  1, 1, 1, 1, ...
   5,  5,  4,  2,  1,  1, 1, 1, 1, ...
   6,  8,  7,  5,  2,  1, 1, 1, 1, ...
   7, 13, 12, 11,  6,  2, 1, 1, 1, ...
   8, 21, 21, 21, 16,  7, 2, 1, 1, ...
   9, 34, 37, 37, 36, 22, 8, 2, 1, ...
		

Crossrefs

Columns 0-9 give A000027(n+1), A000045(n+1), A005251(n+1), A003522, A005676, A099132, A293169, A306721, A306752, A306753.

Programs

  • Mathematica
    T[n_, k_] := Sum[Binomial[n - j, k*j], {j, 0, n}]; Table[T[k, n - k], {n, 0, 11}, {k, 0, n}] // Flatten (* Amiram Eldar, Jun 21 2021 *)

Formula

A(n,k) = Sum_{j=0..n} binomial(n-j,k*j).
A(n,k) = A306713(k*n,k) for k > 0.

A306713 Square array A(n,k), n >= 0, k >= 1, read by antidiagonals, where column k is the expansion of g.f. 1/(1-x^k-x^(k+1)).

Original entry on oeis.org

1, 1, 1, 1, 0, 2, 1, 0, 1, 3, 1, 0, 0, 1, 5, 1, 0, 0, 1, 1, 8, 1, 0, 0, 0, 1, 2, 13, 1, 0, 0, 0, 1, 0, 2, 21, 1, 0, 0, 0, 0, 1, 1, 3, 34, 1, 0, 0, 0, 0, 1, 0, 2, 4, 55, 1, 0, 0, 0, 0, 0, 1, 0, 1, 5, 89, 1, 0, 0, 0, 0, 0, 1, 0, 1, 1, 7, 144, 1, 0, 0, 0, 0, 0, 0, 1, 0, 2, 3, 9, 233
Offset: 0

Views

Author

Seiichi Manyama, Mar 05 2019

Keywords

Comments

A(n,k) is the number of compositions of n into parts k and k+1.

Examples

			Square array begins:
    1, 1, 1, 1, 1, 1, 1, 1, 1, ...
    1, 0, 0, 0, 0, 0, 0, 0, 0, ...
    2, 1, 0, 0, 0, 0, 0, 0, 0, ...
    3, 1, 1, 0, 0, 0, 0, 0, 0, ...
    5, 1, 1, 1, 0, 0, 0, 0, 0, ...
    8, 2, 0, 1, 1, 0, 0, 0, 0, ...
   13, 2, 1, 0, 1, 1, 0, 0, 0, ...
   21, 3, 2, 0, 0, 1, 1, 0, 0, ...
   34, 4, 1, 1, 0, 0, 1, 1, 0, ...
   55, 5, 1, 2, 0, 0, 0, 1, 1, ...
		

Crossrefs

Programs

  • Mathematica
    T[n_, k_] := Sum[Binomial[j, n-k*j], {j, 0, Floor[n/k]}]; Table[T[k, n - k + 1], {n, 0, 12}, {k, 0, n}] // Flatten (* Amiram Eldar, Jun 21 2021 *)

Formula

A(n,k) = Sum_{j=0..floor(n/k)} binomial(j,n-k*j).

A050443 a(0)=4, a(1)=0, a(2)=0, a(3)=3; thereafter a(n) = a(n-3) + a(n-4).

Original entry on oeis.org

4, 0, 0, 3, 4, 0, 3, 7, 4, 3, 10, 11, 7, 13, 21, 18, 20, 34, 39, 38, 54, 73, 77, 92, 127, 150, 169, 219, 277, 319, 388, 496, 596, 707, 884, 1092, 1303, 1591, 1976, 2395, 2894, 3567, 4371, 5289, 6461, 7938, 9660, 11750, 14399, 17598, 21410, 26149, 31997
Offset: 0

Views

Author

Tony Davie (ad(AT)dcs.st-and.ac.uk), Dec 23 1999

Keywords

Comments

Related to Perrin sequence. a(p) is divisible by p for primes p.
Wells states that Mihaly Bencze [Beneze] (1998) proved the divisibility property for this sequence: that a(n) is always divisible by n when n is prime. - Gary W. Adamson, Nov 14 2006
As a(n) = trace(M^n) where M = [0,1,0,0; 0,0,1,0; 0,0,0,1; 1,1,0,0], the previous property comes from the fact that trace(M^n) = trace(M) (= 0) mod n for n prime. - Robert FERREOL, Apr 09 2024

Examples

			a(11) = 11 because a(7) = 7 and a(8) = 4.
		

References

  • David Wells, "Prime Numbers, the Most Mysterious Figures in Math", John Wiley & Sons, Inc.; 2005, p. 103.

Crossrefs

Column 3 of A306646.

Programs

  • GAP
    a:=[4,0,0,3];; for n in [5..60] do a[n]:=a[n-3]+a[n-4]; od; Print(a); # Muniru A Asiru, Mar 09 2019
  • Magma
    I:=[4,0,0,3]; [n le 4 select I[n] else Self(n-3) +Self(n-4): n in [1..60]]; // G. C. Greubel, Mar 04 2019
    
  • Mathematica
    LinearRecurrence[{0,0,1,1}, {4,0,0,3}, 60] (* G. C. Greubel, Mar 04 2019 *)
  • PARI
    polsym(x^4-x-1,55) \\ Joerg Arndt, Mar 04 2019
    
  • Sage
    ((4-x^3)/(1-x^3-x^4)).series(x, 60).coefficients(x, sparse=False) # G. C. Greubel, Mar 04 2019
    

Formula

G.f.: (4-x^3)/(1-x^3-x^4). - Christian G. Bower, Dec 23 1999
a(n) = (x_1)^n + (x_2)^n + (x_3)^n + (x_4)^n where (x_i) 1 <= i <= 4 are the roots of x^4 = x + 1. - Benoit Cloitre, Oct 27 2003
Let M = the 4 X 4 matrix [0,1,0,0; 0,0,1,0; 0,0,0,1; 1,1,0,0]; then a(n) = the leftmost term of M^n * [4,0,0,3]. Example: a(13) = 13 since M^13 * [4,0,0,3] = [13,21,18,20]. - Gary W. Adamson, Nov 14 2006
a(0) = 4 and a(n) = n*Sum_{k=1..floor(n/3)} binomial(k,n-3*k)/k for n > 0. - Seiichi Manyama, Mar 04 2019
From Aleksander Bosek, Mar 10 2019: (Start)
a(n+10) = a(n+5) + 2*a(n+3) + a(n).
a(n+11) = a(n+6) + 3*a(n+1) + 2*a(n).
a(n+12) = a(n+10) + 5*a(n+5) + a(n).
a(n+12) = 3*a(n+5) + a(n+3) + a(n).
a(n+13) = 3*a(n+6) + 2*a(n+1) + a(n).
a(n+14) = 2*a(n+8) + 3*a(n+3) + a(n).
a(n+15) = 2*a(n+7) + 4*a(n+5) + a(n).
a(n+15) = 2*a(n+9) + 4*a(n+1) + 3*a(n).
a(n+19) = a(n+17) + 5*a(n+5) + a(n).
a(n+20) = 5*a(n+10) + 6*a(n+5) + a(n).
a(n+22) = a*(n+21) + 5*a(n+5) + a(n).
a(n+25) = 2*a(n+21) + 5*a(n+5) + a(n).
a((s+4)*n+m) = Sum_{l=0..n} binomial(n-l,l)*a(s*n+l+m) for every m,s > 0.
a(m) = Sum_{l=0..n}(-1)^{n-l}*binomial(n-l,l)*a(m+n+3*l) for every m > 0. (End)
a(n) = 4*A017817(n) - A017817(n-3). - R. J. Mathar, Aug 10 2021

Extensions

More terms from Christian G. Bower, Dec 23 1999
More terms from Benoit Cloitre, Oct 27 2003

A087935 Perrin sequence of order 5.

Original entry on oeis.org

5, 0, 0, 0, 4, 5, 0, 0, 4, 9, 5, 0, 4, 13, 14, 5, 4, 17, 27, 19, 9, 21, 44, 46, 28, 30, 65, 90, 74, 58, 95, 155, 164, 132, 153, 250, 319, 296, 285, 403, 569, 615, 581, 688, 972, 1184, 1196, 1269, 1660, 2156, 2380, 2465, 2929, 3816, 4536, 4845, 5394, 6745, 8352, 9381
Offset: 0

Views

Author

Benoit Cloitre, Oct 27 2003

Keywords

Comments

If p is prime, p divides a(p).

Crossrefs

Column 4 of A306646.
Cf. A087936.

Programs

  • GAP
    a:=[5,0,0,0,4];; for n in [6..60] do a[n]:=a[n-4]+a[n-5]; od; Print(a); # Muniru A Asiru, Mar 06 2019
    
  • Magma
    I:=[5,0,0,0,4]; [n le 5 select I[n] else Self(n-4) +Self(n-5): n in [1..60]]; // G. C. Greubel, Mar 06 2019
    
  • Maple
    seq(coeff(series((x^4-5)/(x^5+x^4-1),x,n+1), x, n), n = 0 .. 60); # Muniru A Asiru, Mar 06 2019
  • Mathematica
    LinearRecurrence[{0,0,0,1,1},{5,0,0,0,4},60] (* Harvey P. Dale, Oct 03 2016 *)
  • PARI
    my(x='x+O('x^60)); Vec((5-x^4)/(1-x^4-x^5)) \\ G. C. Greubel, Mar 06 2019
    
  • PARI
    polsym(x^5-x-1,66) \\ Joerg Arndt, Mar 10 2019
    
  • Sage
    ((5-x^4)/(1-x^4-x^5)).series(x, 60).coefficients(x, sparse=False) # G. C. Greubel, Mar 06 2019

Formula

a(n) = a(n-4) + a(n-5), with a(0)=5, a(1)=a(2)=a(3)=0.
a(n) = (x_1)^n + (x_2)^n + (x_3)^n + (x_4)^n + (x_5)^n where (x_i) 1 <= i <= 5 are the roots of x^5=x+1.
G.f.: (5 - x^4)/(1 -x^4 -x^5). - Colin Barker, Jun 16 2013
a(0) = 5 and a(n) = n*Sum_{k=1..floor(n/4)} binomial(k,n-4*k)/k for n > 0. - Seiichi Manyama, Mar 04 2019
From Aleksander Bosek, Mar 06 2019: (Start)
a((s+5)*n + m) = Sum_{j=0..n} binomial(n-j,j)*a(s*n+j+m) for all s > 0, m > 0.
a(m) = Sum_{j=0..n} (-1)^(n-j)*binomial(n-j,j)*a(m+n+4*j) for all m > 0. (End)

A087936 Perrin sequence of order 6.

Original entry on oeis.org

6, 0, 0, 0, 0, 5, 6, 0, 0, 0, 5, 11, 6, 0, 0, 5, 16, 17, 6, 0, 5, 21, 33, 23, 6, 5, 26, 54, 56, 29, 11, 31, 80, 110, 85, 40, 42, 111, 190, 195, 125, 82, 153, 301, 385, 320, 207, 235, 454, 686, 705, 527, 442, 689, 1140, 1391, 1232, 969, 1131, 1829, 2531, 2623, 2201, 2100
Offset: 0

Views

Author

Benoit Cloitre, Oct 27 2003

Keywords

Comments

If p is prime, p divides a(p).

Crossrefs

Column 5 of A306646.
Cf. A087935.

Programs

  • GAP
    Concatenation([6],List([1..65],n->n*Sum([1..Int(n/5)],k->Binomial(k,n-5*k)/k))); # Muniru A Asiru, Mar 09 2019
    
  • Maple
    a:=n->n*add(binomial(k,n-5*k)/k,k=1..floor(n/5)): 6,seq(a(n),n=1..65); # Muniru A Asiru, Mar 09 2019
  • PARI
    polsym(x^6-x-1,66) \\ Joerg Arndt, Mar 10 2019

Formula

a(n) = a(n-5) + a(n-6) with a(0)=6, a(1)=a(2)=a(3)=a(4)=0, a(5)=5.
a(n) = Sum_{i=1..6} (x_i)^n where x_i are the roots of x^6 = x+1.
G.f.: (x^5-6) / (x^6+x^5-1). - Colin Barker, Jun 16 2013
a(0) = 6 and a(n) = n*Sum_{k=1..floor(n/5)} binomial(k,n-5*k)/k for n > 0. - Seiichi Manyama, Mar 04 2019
From Aleksander Bosek, Mar 06 2019: (Start)
a((s+6)*n+m) = Sum_{l=0..n} binomial(n-l,l)*a(s*n+l+m) for all s > 0, m > 0.
a(m) = Sum_{l=0..n}(-1)^{n-l} binomial(n-l,l)*a(m+n+5*l)for all m > 0. (End)

A306735 Square array A(n,k), n >= 0, k >= 0, read by antidiagonals, where column k is the expansion of g.f. ((k+1-x)*(1-x)^(k-1))/((1-x)^k-x^(k+1)).

Original entry on oeis.org

1, 2, 1, 3, 1, 1, 4, 2, 3, 1, 5, 3, 2, 4, 1, 6, 4, 3, 5, 7, 1, 7, 5, 4, 3, 10, 11, 1, 8, 6, 5, 4, 7, 17, 18, 1, 9, 7, 6, 5, 4, 18, 29, 29, 1, 10, 8, 7, 6, 5, 9, 39, 51, 47, 1, 11, 9, 8, 7, 6, 5, 28, 73, 90, 76, 1, 12, 10, 9, 8, 7, 6, 11, 74, 127, 158, 123, 1, 13, 11, 10, 9, 8, 7, 6, 40, 164, 219, 277, 199, 1
Offset: 0

Views

Author

Seiichi Manyama, Mar 06 2019

Keywords

Examples

			Square array begins:
   1,  2,  3,   4,   5,   6,  7,  8, 9, ...
   1,  1,  2,   3,   4,   5,  6,  7, 8, ...
   1,  3,  2,   3,   4,   5,  6,  7, 8, ...
   1,  4,  5,   3,   4,   5,  6,  7, 8, ...
   1,  7, 10,   7,   4,   5,  6,  7, 8, ...
   1, 11, 17,  18,   9,   5,  6,  7, 8, ...
   1, 18, 29,  39,  28,  11,  6,  7, 8, ...
   1, 29, 51,  73,  74,  40, 13,  7, 8, ...
   1, 47, 90, 127, 164, 125, 54, 15, 8, ...
		

Crossrefs

Columns 0-2 give A000012, A000032, A259967.

Formula

A(n,k) = A306646(k*n,k) for k > 0.
A(n,k) = (k+1)*A306680(n,k) - A306680(n-1,k) for n > 0.

A306755 a(n) = a(n-6) + a(n-7) with a(0)=7, a(1)=...=a(5)=0, a(6)=6.

Original entry on oeis.org

7, 0, 0, 0, 0, 0, 6, 7, 0, 0, 0, 0, 6, 13, 7, 0, 0, 0, 6, 19, 20, 7, 0, 0, 6, 25, 39, 27, 7, 0, 6, 31, 64, 66, 34, 7, 6, 37, 95, 130, 100, 41, 13, 43, 132, 225, 230, 141, 54, 56, 175, 357, 455, 371, 195, 110, 231, 532, 812, 826, 566, 305, 341, 763, 1344, 1638, 1392, 871, 646, 1104, 2107
Offset: 0

Views

Author

Seiichi Manyama, Mar 08 2019

Keywords

Comments

Conjecture: If p is prime, p divides a(p).

Crossrefs

Column 6 of A306646.

Programs

  • Mathematica
    LinearRecurrence[{0, 0, 0, 0, 0, 1, 1}, {7, 0, 0, 0, 0, 0, 6}, 100] (* Amiram Eldar, Jun 21 2021 *)
  • PARI
    N=66; x='x+O('x^N); Vec((7-x^6)/(1-x^6-x^7))

Formula

G.f.: (7 - x^6)/(1 - x^6 - x^7).
a(0) = 7 and a(n) = n*Sum_{k=1..floor(n/6)} binomial(k,n-6*k)/k for n > 0.

A306756 a(n) = a(n-7) + a(n-8) with a(0)=8, a(1)=...=a(6)=0, a(7)=7.

Original entry on oeis.org

8, 0, 0, 0, 0, 0, 0, 7, 8, 0, 0, 0, 0, 0, 7, 15, 8, 0, 0, 0, 0, 7, 22, 23, 8, 0, 0, 0, 7, 29, 45, 31, 8, 0, 0, 7, 36, 74, 76, 39, 8, 0, 7, 43, 110, 150, 115, 47, 8, 7, 50, 153, 260, 265, 162, 55, 15, 57, 203, 413, 525, 427, 217, 70, 72, 260, 616, 938, 952, 644, 287, 142
Offset: 0

Views

Author

Seiichi Manyama, Mar 08 2019

Keywords

Comments

Conjecture: If p is prime, p divides a(p).

Crossrefs

Column 7 of A306646.

Programs

  • Mathematica
    LinearRecurrence[{0, 0, 0, 0, 0, 0, 1, 1}, {8, 0, 0, 0, 0, 0, 0, 7}, 100] (* Amiram Eldar, Jun 21 2021 *)
  • PARI
    N=66; x='x+O('x^N); Vec((8-x^7)/(1-x^7-x^8))

Formula

G.f.: (8 - x^7)/(1 - x^7 - x^8).
a(0) = 8 and a(n) = n*Sum_{k=1..floor(n/7)} binomial(k,n-7*k)/k for n > 0.

A306757 a(n) = a(n-8) + a(n-9) with a(0)=9, a(1)=...=a(7)=0, a(8)=8.

Original entry on oeis.org

9, 0, 0, 0, 0, 0, 0, 0, 8, 9, 0, 0, 0, 0, 0, 0, 8, 17, 9, 0, 0, 0, 0, 0, 8, 25, 26, 9, 0, 0, 0, 0, 8, 33, 51, 35, 9, 0, 0, 0, 8, 41, 84, 86, 44, 9, 0, 0, 8, 49, 125, 170, 130, 53, 9, 0, 8, 57, 174, 295, 300, 183, 62, 9, 8, 65, 231, 469, 595, 483, 245, 71, 17, 73, 296, 700
Offset: 0

Views

Author

Seiichi Manyama, Mar 08 2019

Keywords

Comments

Conjecture: If p is prime, p divides a(p).

Crossrefs

Column 8 of A306646.

Programs

  • Mathematica
    LinearRecurrence[{0, 0, 0, 0, 0, 0, 0, 1, 1}, {9, 0, 0, 0, 0, 0, 0, 0, 8}, 100] (* Amiram Eldar, Jun 21 2021 *)
  • PARI
    N=99; x='x+O('x^N); Vec((9-x^8)/(1-x^8-x^9))

Formula

G.f.: (9 - x^8)/(1 - x^8 - x^9).
a(0) = 9 and a(n) = n*Sum_{k=1..floor(n/8)} binomial(k,n-8*k)/k for n > 0.

A306758 a(n) = a(n-9) + a(n-10) with a(0)=10, a(1)=...=a(8)=0, a(9)=9.

Original entry on oeis.org

10, 0, 0, 0, 0, 0, 0, 0, 0, 9, 10, 0, 0, 0, 0, 0, 0, 0, 9, 19, 10, 0, 0, 0, 0, 0, 0, 9, 28, 29, 10, 0, 0, 0, 0, 0, 9, 37, 57, 39, 10, 0, 0, 0, 0, 9, 46, 94, 96, 49, 10, 0, 0, 0, 9, 55, 140, 190, 145, 59, 10, 0, 0, 9, 64, 195, 330, 335, 204, 69, 10, 0, 9, 73, 259, 525, 665
Offset: 0

Views

Author

Seiichi Manyama, Mar 08 2019

Keywords

Comments

Conjecture: If p is prime, p divides a(p).

Crossrefs

Column 9 of A306646.

Programs

  • Mathematica
    LinearRecurrence[{0,0,0,0,0,0,0,0,1,1},{10,0,0,0,0,0,0,0,0,9},80] (* Harvey P. Dale, Jan 18 2021 *)
  • PARI
    N=99; x='x+O('x^N); Vec((10-x^9)/(1-x^9-x^10))

Formula

G.f.: (10 - x^9)/(1 - x^9 - x^10).
a(0) = 10 and a(n) = n*Sum_{k=1..floor(n/9)} binomial(k,n-9*k)/k for n > 0.
Showing 1-10 of 10 results.