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.

Previous Showing 11-19 of 19 results.

A077593 Table by antidiagonals where T(n,k) = Sum_{i=1..n} T(floor(n/i),k-1) starting with T(n,0)=1 if n>0 and T(0,0)=0.

Original entry on oeis.org

0, 0, 1, 0, 1, 1, 0, 1, 2, 1, 0, 1, 3, 3, 1, 0, 1, 4, 5, 4, 1, 0, 1, 5, 7, 8, 5, 1, 0, 1, 6, 9, 13, 10, 6, 1, 0, 1, 7, 11, 19, 16, 14, 7, 1, 0, 1, 8, 13, 26, 23, 25, 16, 8, 1, 0, 1, 9, 15, 34, 31, 39, 28, 20, 9, 1, 0, 1, 10, 17, 43, 40, 56, 43, 38, 23, 10, 1, 0, 1, 11, 19, 53, 50, 76, 61, 63
Offset: 0

Views

Author

Henry Bottomley, Nov 08 2002

Keywords

Examples

			Rows start:
 0,0,0,0,0,0...;
 1,1,1,1,1,1...;
 1,2,3,4,5,6...;
 1,3,5,7,9,11...;
 1,4,8,13,19,26,...;
 ...

Crossrefs

Columns include A057427, A001477, A006218, A061201, A061202, A061203, A061204.
Rows include (with offsets) A000004, A000012, A000027, A005408, A034856, A052905.
Cf. A077593.

Formula

T(n, k) = T(n-1, k) + A077592(n, k). Writing m as Sum_{i} p_i^e_i, T(n, k) = Sum_{m=1..n} Product_{i} C(k+e_i-1, e_i).

A135855 A007318 * a tridiagonal matrix with (1, 4, 1, 0, 0, 0, ...) in every column.

Original entry on oeis.org

1, 5, 1, 10, 6, 1, 16, 16, 7, 1, 23, 32, 23, 8, 1, 31, 55, 55, 31, 9, 1, 40, 86, 110, 86, 40, 10, 1, 50, 126, 196, 196, 126, 50, 11, 1, 61, 176, 322, 392, 322, 176, 61, 12, 1, 73, 237, 498, 714, 714, 498, 237, 73, 13, 1
Offset: 0

Views

Author

Gary W. Adamson, Dec 01 2007

Keywords

Examples

			First few rows of the triangle:
   1;
   5,  1;
  10,  6,   1;
  16, 16,   7,  1;
  23, 32,  23,  8,  1;
  31, 55,  55, 31,  9,  1;
  40, 86, 110, 86, 40, 10, 1;
  ...

Links

Crossrefs

Cf. A007318, A022815, A052905, A101945, A134465.

Programs

  • Magma
    A135855:= func< n,k | Binomial(n,k)*(n^2 + (2*k+7)*n - 2*(k^2 + 2*k -1))/((k+1)*(k+2)) >;
[A135855(n,k): k in [0..n], n in [0..10]]; // G. C. Greubel, Feb 06 2022
  • Mathematica
    T[n_, k_]:= T[n, k]= If[k<0 || k>n, 0, If[k==0, (n^2+7*n+2)/2, If[k==n, 1, T[n-1, k-1] + T[n-1, k]]]];
Table[T[n, k], {n,0,12}, {k,0,n}]//Flatten (* G. C. Greubel, Feb 06 2022 *)
  • Sage
    @CachedFunction
def T(n,k): # A135855
    if (k==0): return (n^2+7*n+2)/2
    elif (k==n): return 1
    else: return T(n-1, k-1) + T(n-1, k)
flatten([[T(n,k) for k in (0..n)] for n in (0..10)]) # G. C. Greubel, Feb 06 2022

Formula

Binomial transform of an infinite tridiagonal matrix with (1, 4, 1, 0, 0, 0, ...) in every column; i.e., (1, 1, 1, ...) in the main diagonal, (4, 4, 4, 0, 0, 0, ...) in the subdiagonal and (1, 1, 1, ...) in the subsubdiagonal.
T(n, 0) = A052905(n).
Sum_{k=0..n} T(n, k) = A101945(n).
From G. C. Greubel, Feb 06 2022: (Start)
T(n, k) = T(n-1, k-1) + T(n-1, k), with T(n, n) = 1, T(n, 0) = A052905(n).
T(n, k) = binomial(n,k)*(n^2 + (2*k+7)*n - 2*(k^2 + 2*k -1))/((k+1)*(k+2)).
T(n, 1) = A134465(n).
T(n, 2) = A022815(n-1).
T(n, n-1) = n+3.
T(n, n-2) = A052905(n+2). (End)

A131414 A130302 + A130303 - A000012.

Original entry on oeis.org

1, 5, 1, 10, 3, 1, 16, 5, 3, 1, 23, 7, 5, 3, 1, 31, 9, 7, 5, 3, 1, 40, 11, 9, 7, 5, 3, 1, 50, 13, 11, 9, 7, 5, 3, 1, 61, 15, 13, 11, 9, 7, 5, 3, 1, 73, 17, 15, 13, 11, 9, 7, 5, 3, 1
Offset: 1

Views

Author

Gary W. Adamson, Jul 08 2007

Keywords

Comments

Left column = A052905: (1, 5, 10, 16, 23, 31,...). Row sums = A095794: (1, 6, 14, 25, 39,...).

Examples

			First few rows of the triangle are:
1;
5, 1;
10, 3, 1;
16, 5, 3, 1;
23, 7, 5, 3, 1;
31, 9, 7, 5, 3, 1;
...

Crossrefs

Cf. A130302, A130303, A052905, A095794.

Formula

A130302 + A130303 - A000012 as infinite lower triangular matrices.

A131899 A002260 + A131821 - A000012.

Original entry on oeis.org

1, 2, 3, 3, 2, 5, 4, 2, 3, 7, 5, 2, 3, 4, 9, 6, 2, 3, 4, 5, 11, 7, 2, 3, 4, 5, 6, 13, 8, 2, 3, 4, 5, 6, 7, 15, 9, 2, 3, 4, 5, 6, 7, 8, 17, 10, 2, 3, 4, 5, 6, 7, 8, 9, 19
Offset: 0

Views

Author

Gary W. Adamson, Jul 25 2007

Keywords

Comments

Row sums = A052905: (1, 5, 10, 16, 23, ...)

Examples

			First few rows of the triangle:
  1;
  2,  3;
  3,  2,  5;
  4,  2,  3,  7;
  5,  2,  3,  4,  9;
  6,  2,  3,  4,  5, 11;
  7,  2,  3,  4,  5,  6, 13;
  ...

Crossrefs

Cf. A002260, A131821, A052905.

Formula

A002260 + A131821 - A000012 as infinite lower triangular matrices.

A134199 A002260 + A134082 - I as infinite lower triangular matrices; I = Identity matrix.

Original entry on oeis.org

1, 3, 2, 1, 6, 3, 1, 2, 9, 4, 1, 2, 3, 12, 5, 1, 2, 3, 4, 15, 6, 1, 2, 3, 4, 5, 18, 7, 1, 2, 3, 4, 5, 6, 21, 8, 1, 2, 3, 4, 5, 6, 7, 24, 9, 1, 2, 3, 4, 5, 6, 7, 8, 27, 10
Offset: 0

Views

Author

Gary W. Adamson, Oct 13 2007

Keywords

Comments

Row sums = A052905: (1, 5, 10, 16, 23, 31, 40, ...).

Examples

			First few rows of the triangle:
  1;
  3,  2;
  1,  6,  3;
  1,  2,  9,  4;
  1,  2,  3, 12,  5;
  1,  2,  3,  4, 15,  6;
  1,  2,  3,  4,  5, 18,  7;
  ...

Crossrefs

Cf. A002260, A134082, A052905.

A158860 Triangle T(n,k)= ( 1 +T(n-1,k)*T(n,k-1) ) / T(n-1,k-1) initialized by T(n,0)=3n-2, T(n,k)=0 if k>=n, read by rows 0<=k

Original entry on oeis.org

1, 4, 1, 7, 2, 1, 10, 3, 2, 1, 13, 4, 3, 2, 1, 16, 5, 4, 3, 2, 1, 19, 6, 5, 4, 3, 2, 1, 22, 7, 6, 5, 4, 3, 2, 1, 25, 8, 7, 6, 5, 4, 3, 2, 1, 28, 9, 8, 7, 6, 5, 4, 3, 2, 1
Offset: 1

Views

Author

Roger L. Bagula and Gary W. Adamson, Mar 28 2009

Keywords

Comments

Row sums are in A052905.

Examples

			1;
4, 1;
7, 2, 1;
10, 3, 2, 1;
13, 4, 3, 2, 1;
16, 5, 4, 3, 2, 1;
19, 6, 5, 4, 3, 2, 1;
22, 7, 6, 5, 4, 3, 2, 1;
25, 8, 7, 6, 5, 4, 3, 2, 1;
28, 9, 8, 7, 6, 5, 4, 3, 2, 1;

References

  • H. S. M. Coxeter, Regular Polytopes, 3rd ed., Dover, NY, 1973, pp 159-162.

Crossrefs

Cf. A130303

Programs

  • Maple
    A158860 := proc(n,k)
    option remember;
    if k = 0 then
        3*n-2 ;
    elif k >= n then
        0 ;
    else
        (1+procname(n-1,k)*procname(n,k-1))/procname(n-1,k-1) ;
    end if;
end proc: # R. J. Mathar, Jul 11 2012
  • Mathematica
    Clear[e, n, k];
e[n_, 0] := 3*n - 2;
e[n_, k_] := 0 /; k >= n;
e[n_, k_] := (e[n - 1, k]*e[n, k - 1] + 1)/e[n - 1, k - 1];
Table[Table[e[n, k], {k, 0, n - 1}], {n, 1, 10}];
Flatten[%]

Formula

T(n,k) = n-k, k>=1. - R. J. Mathar, Jul 11 2012

A188461 A Deutsch-Fibonacci triangle.

Original entry on oeis.org

1, 1, 1, 1, 5, 1, 1, 10, 10, 1, 1, 16, 39, 16, 1, 1, 23, 99, 99, 23, 1, 1, 31, 203, 375, 203, 31, 1, 1, 40, 366, 1065, 1065, 366, 40, 1, 1, 50, 605, 2521, 4027, 2521, 605, 50, 1, 1, 61, 939, 5266, 12220, 12220, 5266, 939, 61, 1
Offset: 0

Views

Author

Paul Barry, Apr 01 2011

Keywords

Comments

Second column is A052905. Third column is A188480.

Examples

			Triangle begins
1,
1, 1,
1, 5, 1,
1, 10, 10, 1,
1, 16, 39, 16, 1,
1, 23, 99, 99, 23, 1,
1, 31, 203, 375, 203, 31, 1,
1, 40, 366, 1065, 1065, 366, 40, 1,
1, 50, 605, 2521, 4027, 2521, 605, 50, 1,
1, 61, 939, 5266, 12220, 12220, 5266, 939, 61, 1

Crossrefs

Cf. A100754, A188474.

Formula

T(n,k)=sum{j=0..n-k+1, (j/(n+2-j))C(n+2-j,n-k+1)*C(n+2-j,k+1)*F(j+1)}.

A303273 Array T(n,k) = binomial(n, 2) + k*n + 1 read by antidiagonals.

Original entry on oeis.org

1, 1, 1, 1, 2, 2, 1, 3, 4, 4, 1, 4, 6, 7, 7, 1, 5, 8, 10, 11, 11, 1, 6, 10, 13, 15, 16, 16, 1, 7, 12, 16, 19, 21, 22, 22, 1, 8, 14, 19, 23, 26, 28, 29, 29, 1, 9, 16, 22, 27, 31, 34, 36, 37, 37, 1, 10, 18, 25, 31, 36, 40, 43, 45, 46, 46, 1, 11, 20, 28, 35, 41
Offset: 0

Views

Author

Franck Maminirina Ramaharo, Apr 20 2018

Keywords

Comments

Columns are linear recurrence sequences with signature (3,-3,1).
8*T(n,k) + A166147(k-1) are squares.
Columns k are binomial transforms of [1, k, 1, 0, 0, 0, ...].
Antidiagonals sums yield A116731.

Examples

			The array T(n,k) begins
1    1    1    1    1    1    1    1    1    1    1    1    1  ...  A000012
1    2    3    4    5    6    7    8    9   10   11   12   13  ...  A000027
2    4    6    8   10   12   14   16   18   20   22   24   26  ...  A005843
4    7   10   13   16   19   22   25   28   31   34   37   40  ...  A016777
7   11   15   19   23   27   31   35   39   43   47   51   55  ...  A004767
11  16   21   26   31   36   41   46   51   56   61   66   71  ...  A016861
16  22   28   34   40   46   52   58   64   70   76   82   88  ...  A016957
22  29   36   43   50   57   64   71   78   85   92   99  106  ...  A016993
29  37   45   53   61   69   77   85   93  101  109  117  125  ...  A004770
37  46   55   64   73   82   91  100  109  118  127  136  145  ...  A017173
46  56   66   76   86   96  106  116  126  136  146  156  166  ...  A017341
56  67   78   89  100  111  122  133  144  155  166  177  188  ...  A017401
67  79   91  103  115  127  139  151  163  175  187  199  211  ...  A017605
79  92  105  118  131  144  157  170  183  196  209  222  235  ...  A190991
...
The inverse binomial transforms of the columns are
1    1    1    1    1    1    1    1    1    1    1    1    1  ...
0    1    2    3    4    5    6    7    8    9   10   11   12  ...
1    1    1    1    1    1    1    1    1    1    1    1    1  ...
0    0    0    0    0    0    0    0    0    0    0    0    0  ...
0    0    0    0    0    0    0    0    0    0    0    0    0  ...
0    0    0    0    0    0    0    0    0    0    0    0    0  ...
...
T(k,n-k) = A087401(n,k) + 1 as triangle
1
1   1
1   2   2
1   3   4   4
1   4   6   7   7
1   5   8  10  11  11
1   6  10  13  15  16  16
1   7  12  16  19  21  22  22
1   8  14  19  23  26  28  29  29
1   9  16  22  27  31  34  36  37  37
1  10  18  25  31  36  40  43  45  46  46
...

References

  • R. L. Graham, D. E. Knuth and O. Patashnik, Concrete Mathematics: A Foundation for Computer Science, Addison-Wesley, 1994.

Crossrefs

Cf. A085475, A086270, A086271, A086272, A086273, A130154, A159798, A162609, A162610, A300401.

Programs

  • Maple
    T := (n, k) -> binomial(n, 2) + k*n + 1;
for n from 0 to 20 do seq(T(n, k), k = 0 .. 20) od;
  • Mathematica
    Table[With[{n = m - k}, Binomial[n, 2] + k n + 1], {m, 0, 11}, {k, m, 0, -1}] // Flatten (* Michael De Vlieger, Apr 21 2018 *)
  • Maxima
    T(n, k) := binomial(n, 2)+ k*n + 1$
for n:0 thru 20 do
    print(makelist(T(n, k), k, 0, 20));
  • PARI
    T(n,k) = binomial(n, 2) + k*n + 1;
tabl(nn) = for (n=0, nn, for (k=0, nn, print1(T(n, k), ", ")); print); \\ Michel Marcus, May 17 2018

Formula

G.f.: (3*x^2*y - 3*x*y + y - 2*x^2 + 2*x - 1)/((x - 1)^3*(y - 1)^2).
E.g.f.: (1/2)*(2*x*y + x^2 + 2)*exp(y + x).
T(n,k) = 3*T(n-1,k) - 3*T(n-2,k) + T(n-3,k), with T(0,k) = 1, T(1,k) = k + 1 and T(2,k) = 2*k + 2.
T(n,k) = T(n-1,k) + n + k - 1.
T(n,k) = T(n,k-1) + n, with T(n,0) = 1.
T(n,0) = A152947(n+1).
T(n,1) = A000124(n).
T(n,2) = A000217(n).
T(n,3) = A034856(n+1).
T(n,4) = A052905(n).
T(n,5) = A051936(n+4).
T(n,6) = A246172(n+1).
T(n,7) = A302537(n).
T(n,8) = A056121(n+1) + 1.
T(n,9) = A056126(n+1) + 1.
T(n,10) = A051942(n+10) + 1, n > 0.
T(n,11) = A101859(n) + 1.
T(n,12) = A132754(n+1) + 1.
T(n,13) = A132755(n+1) + 1.
T(n,14) = A132756(n+1) + 1.
T(n,15) = A132757(n+1) + 1.
T(n,16) = A132758(n+1) + 1.
T(n,17) = A212427(n+1) + 1.
T(n,18) = A212428(n+1) + 1.
T(n,n) = A143689(n) = A300192(n,2).
T(n,n+1) = A104249(n).
T(n,n+2) = T(n+1,n) = A005448(n+1).
T(n,n+3) = A000326(n+1).
T(n,n+4) = A095794(n+1).
T(n,n+5) = A133694(n+1).
T(n+2,n) = A005449(n+1).
T(n+3,n) = A115067(n+2).
T(n+4,n) = A133694(n+2).
T(2*n,n) = A054556(n+1).
T(2*n,n+1) = A054567(n+1).
T(2*n,n+2) = A033951(n).
T(2*n,n+3) = A001107(n+1).
T(2*n,n+4) = A186353(4*n+1) (conjectured).
T(2*n,n+5) = A184103(8*n+1) (conjectured).
T(2*n,n+6) = A250657(n-1) = A250656(3,n-1), n > 1.
T(n,2*n) = A140066(n+1).
T(n+1,2*n) = A005891(n).
T(n+2,2*n) = A249013(5*n+4) (conjectured).
T(n+3,2*n) = A186384(5*n+3) = A186386(5*n+3) (conjectured).
T(2*n,2*n) = A143689(2*n).
T(2*n+1,2*n+1) = A143689(2*n+1) (= A030503(3*n+3) (conjectured)).
T(2*n,2*n+1) = A104249(2*n) = A093918(2*n+2) = A131355(4*n+1) (= A030503(3*n+5) (conjectured)).
T(2*n+1,2*n) = A085473(n).
a(n+1,5*n+1)=A051865(n+1) + 1.
a(n,2*n+1) = A116668(n).
a(2*n+1,n) = A054569(n+1).
T(3*n,n) = A025742(3*n-1), n > 1 (conjectured).
T(n,3*n) = A140063(n+1).
T(n+1,3*n) = A069099(n+1).
T(n,4*n) = A276819(n).
T(4*n,n) = A154106(n-1), n > 0.
T(2^n,2) = A028401(n+2).
T(1,n)*T(n,1) = A006000(n).
T(n*(n+1),n) = A211905(n+1), n > 0 (conjectured).
T(n*(n+1)+1,n) = A294259(n+1).
T(n,n^2+1) = A081423(n).
T(n,A000217(n)) = A158842(n), n > 0.
T(n,A152947(n+1)) = A060354(n+1).
floor(T(n,n/2)) = A267682(n) (conjectured).
floor(T(n,n/3)) = A025742(n-1), n > 0 (conjectured).
floor(T(n,n/4)) = A263807(n-1), n > 0 (conjectured).
ceiling(T(n,2^n)/n) = A134522(n), n > 0 (conjectured).
ceiling(T(n,n/2+n)/n) = A051755(n+1) (conjectured).
floor(T(n,n)/n) = A133223(n), n > 0 (conjectured).
ceiling(T(n,n)/n) = A007494(n), n > 0.
ceiling(T(n,n^2)/n) = A171769(n), n > 0.
ceiling(T(2*n,n^2)/n) = A046092(n), n > 0.
ceiling(T(2*n,2^n)/n) = A131520(n+2), n > 0.

A134224 A004736 + A134082 - I as infinite lower triangular matrices; I = Identity matrix.

Original entry on oeis.org

1, 4, 1, 3, 6, 1, 4, 3, 8, 1, 5, 4, 3, 10, 1, 6, 5, 4, 3, 12, 1, 7, 6, 5, 4, 3, 14, 1, 8, 7, 6, 5, 4, 3, 16, 1, 9, 8, 7, 6, 5, 4, 3, 18, 1, 10, 9, 8, 7, 6, 5, 4, 3, 20, 1
Offset: 0

Views

Author

Gary W. Adamson, Oct 14 2007

Keywords

Comments

Row sums = A052905: (1, 5, 10, 16, 23, 31, 40, ...).

Examples

			First few rows of the triangle:
  1;
  4,  1;
  3,  6,  1;
  4,  3,  8,  1;
  5,  4,  3, 10,  1;
  6,  5,  4,  3, 12,  1;
  7,  6,  5,  4,  3, 14,  1;
  ...

Crossrefs

Cf. A004736, A052905, A134082.
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