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 30 results. Next

A185874 Second accumulation array of A051340, by antidiagonals.

Original entry on oeis.org

1, 3, 4, 6, 11, 10, 10, 21, 26, 20, 15, 34, 48, 50, 35, 21, 50, 76, 90, 85, 56, 28, 69, 110, 140, 150, 133, 84, 36, 91, 150, 200, 230, 231, 196, 120, 45, 116, 196, 270, 325, 350, 336, 276, 165, 55, 144, 248, 350, 435, 490, 504, 468, 375, 220, 66, 175, 306, 440, 560, 651, 700, 696, 630, 495, 286, 78, 209, 370, 540, 700, 833, 924, 960, 930, 825, 638, 364, 91, 246, 440, 650, 855, 1036, 1176, 1260, 1275, 1210, 1056, 806, 455, 105, 286, 516, 770, 1025, 1260, 1456, 1596, 1665, 1650, 1540, 1326, 1001, 560
Offset: 1

Views

Author

Clark Kimberling, Feb 05 2011

Keywords

Comments

A member of the accumulation chain: A051340 < A141419 < A185874 < A185875 < A185876 < ... (See A144112 for the definition of accumulation array.)

Examples

			Northwest corner:
.   1,   3,   6,   10,   15,   21,   28,   36,   45,   55, ...
.   4,  11,  21,   34,   50,   69,   91,  116,  144,  175, ...
.  10,  26,  48,   76,  110,  150,  196,  248,  306,  370, ...
.  20,  50,  90,  140,  200,  270,  350,  440,  540,  650, ...
.  35,  85, 150,  230,  325,  435,  560,  700,  855, 1025, ...
.  56, 133, 231,  350,  490,  651,  833, 1036, 1260, 1505, ...
.  84, 196, 336,  504,  700,  924, 1176, 1456, 1764, 2100, ...
. 120, 276, 468,  696,  960, 1260, 1596, 1968, 2376, 2820, ...
. 165, 375, 630,  930, 1275, 1665, 2100, 2580, 3105, 3675, ...
. 220, 495, 825, 1210, 1650, 2145, 2695, 3300, 3960, 4675, ...
...
		

Crossrefs

Row 1 to 5: A000217, A115056, 2*A140096, 10*A000096, 5*A059845.
Column 1 to 3: A000292, A051925, A267370 and 3*A005581.
Main diagonal: A117066.

Programs

  • Mathematica
    f[n_, k_] := (1/12)*k*n*(1 + n)*(1 + 3*k + 2*n);
    TableForm[Table[f[n, k], {n, 1, 10}, {k, 1, 15}]]
    Table[f[n - k + 1, k], {n, 14}, {k, n, 1, -1}] // Flatten

Formula

T(n,k) = k*n*(n+1)*(2*n+3*k+1)/12 for k>=1, n>=1.

Extensions

Edited by Bruno Berselli, Jan 14 2016

A185875 Third accumulation array of A051340, by antidiagonals.

Original entry on oeis.org

1, 4, 5, 10, 19, 15, 20, 46, 55, 35, 35, 90, 130, 125, 70, 56, 155, 250, 290, 245, 126, 84, 245, 425, 550, 560, 434, 210, 120, 364, 665, 925, 1050, 980, 714, 330, 165, 516, 980, 1435, 1750, 1820, 1596, 1110, 495, 220, 705, 1380, 2100, 2695, 3010, 2940, 2460, 1650, 715, 286, 935, 1875, 2940, 3920, 4606, 4830, 4500, 3630, 2365, 1001, 364, 1210, 2475, 3975, 5460, 6664, 7350, 7350, 6600, 5170
Offset: 1

Views

Author

Clark Kimberling, Feb 05 2011

Keywords

Comments

A member of the accumulation chain A051340 < A141419 < A185874 < A185875 < A185876 < ... (See A144112 for the definition of accumulation array.)

Examples

			Northwest corner:
   1,   4,  10,  20,  35
   5,  19,  46,  90, 155
  15,  55, 130, 250, 425
  35, 125, 290, 550, 925
		

Crossrefs

Row 1: A000292; Column 1: A000332.

Programs

  • Mathematica
    f[n_,k_]:= k*(1+k)*n*(1+n)*(2+n)*(5+4*k+3*n)/144;
    TableForm[Table[f[n,k],{n,1,10},{k,1,15}]]
    Table[f[n-k+1,k],{n,14},{k,n,1,-1}]//Flatten

Formula

T(n,k) = (3*n+4*k+5)*C(k,2)*C(n,3)/12, k>=1, n>=1.

A185876 Fourth accumulation array of A051340, by antidiagonals.

Original entry on oeis.org

1, 5, 6, 15, 29, 21, 35, 85, 99, 56, 70, 195, 285, 259, 126, 126, 385, 645, 735, 574, 252, 210, 686, 1260, 1645, 1610, 1134, 462, 330, 1134, 2226, 3185, 3570, 3150, 2058, 792, 495, 1770, 3654, 5586, 6860, 6930, 5670, 3498, 1287, 715, 2640, 5670, 9114, 11956, 13230, 12390, 9570, 5643, 2002, 1001, 3795, 8415, 14070
Offset: 1

Views

Author

Clark Kimberling, Feb 05 2011

Keywords

Comments

A member of the accumulation chain A051340 < A141419 < A185874 < A185875 < A185876 < ... (See A144112 for the definition of accumulation array.)

Examples

			Northwest corner:
   1,   5,  15,   35,   70
   6,  29,  85,  195,  385
  21,  99, 285,  645, 1260
  56, 259, 735, 1645, 3185
		

Crossrefs

Row 1: A000332, column 1: A000389.

Programs

  • Mathematica
    f[n_,k_]:=k(1+k)n(1+n)(2+n)(5+4k+3n)/144;
    TableForm[Table[f[n,k],{n,1,10},{k,1,15}]] (* A185875 *)
    Table[f[n-k+1,k],{n,14},{k,n,1,-1}]//Flatten
    s[n_,k_]:=Sum[f[i,j],{i,1,n},{j,1,k}]; (* accumulation array of {f(n,k)} *)
    Factor[s[n,k]]  (* formula for A185876 *)
    TableForm[Table[s[n,k],{n,1,10},{k,1,15}]] (* A185876 *)
    Table[s[n-k+1,k],{n,14},{k,n,1,-1}]//Flatten

Formula

T(n,k) = (4*n+5*k+11)*C(k+2,3)*C(n+4,4)/20, k>=1, n>=1.

A131914 3*A002024 - 2*A051340.

Original entry on oeis.org

1, 4, 2, 7, 5, 3, 10, 8, 6, 4, 13, 11, 9, 7, 5, 16, 14, 12, 10, 8, 6, 19, 17, 15, 13, 11, 9, 7, 22, 20, 18, 16, 14, 12, 10, 8, 25, 23, 21, 19, 17, 15, 13, 11, 9, 28, 26, 24, 22, 20, 18, 16, 14, 12, 10
Offset: 1

Views

Author

Gary W. Adamson, Jul 27 2007

Keywords

Comments

Row sums = the hexagonal numbers, A000384: (1, 6, 15, 28, 45, ...).
From Boris Putievskiy, Jan 24 2013: (Start)
Table T(n,k) = n + 3*k - 3, n, k > 0, read by antidiagonals. General case A209304. Let m be a positive integer. The first column of the table T(n,1) is the sequence of the positive integers A000027. Every subsequent column is formed from the previous column, shifted by m elements.
For m=0 the result is A002260,
for m=1 the result is A002024,
for m=2 the result is A128076,
for m=3 the result is A131914,
for m=4 the result is A209304. (End)

Examples

			First few rows of the triangle:
   1;
   4,  2;
   7,  5,  3;
  10,  8,  6,  4;
  13, 11,  9,  7,  5;
  16, 14, 12, 10,  8,  6;
  19, 17, 15, 13, 11,  9,  7;
  ...
		

Crossrefs

Formula

3*A002024 - 2*A051340 as infinite lower triangular matrices.
From Boris Putievskiy, Jan 24 2013: (Start)
For the general case
a(n) = m*A003056 - (m-1)*A002260.
a(n) = m*(t+1) + (m-1)*(t*(t+1)/2-n), where t = floor((-1+sqrt(8*n-7))/2).
For m = 3,
a(n) = 3*A003056 - 2*A002260.
a(n) = 3*(t+1) + 2*(t*(t+1)/2-n), where t = floor((-1+sqrt(8*n-7))/2). (End)

A127949 A000012 as an infinite lower triangular matrix with all 1's; A127899 = a simple transform; then A000012 * A127899. Given A051340, change all 1's to -1. Triangle read by rows, (n-1) -1's followed by "n".

Original entry on oeis.org

1, -1, 2, -1, -1, 3, -1, -1, -1, 4, -1, -1, -1, -1, 5, -1, -1, -1, -1, -1, 6, -1, -1, -1, -1, -1, -1, 7, -1, -1, -1, -1, -1, -1, -1, 8, -1, -1, -1, -1, -1, -1, -1, -1, 9, -1, -1, -1, -1, -1, -1, -1, -1, -1, 10, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 11, -1, -1, -1, -1, -1, -1
Offset: 1

Views

Author

Gary W. Adamson, Feb 09 2007

Keywords

Comments

For the inverse of A127949 see A126615, a harmonic triangle.
This is one way to define an inverse to A000217. - R. J. Mathar, Apr 30 2010

Examples

			First few rows of the triangle are:
1;
-1, 2;
-1, -1, 3;
-1, -1, -1, 4;
...
		

Crossrefs

Programs

  • Maple
    A127949 := proc(n) if issqr(1+8*n) then (sqrt(1+8*n)-1)/2 ; else -1 ; end if; end proc: seq(A127949(n),n=1..120) ; # R. J. Mathar, Apr 30 2010

Extensions

More terms from R. J. Mathar, Apr 30 2010

A130298 A051340 * A130296.

Original entry on oeis.org

1, 5, 2, 12, 4, 3, 22, 6, 5, 4, 35, 8, 7, 6, 5, 51, 10, 9, 8, 7, 6, 70, 12, 11, 10, 9, 8, 7, 92, 14, 13, 12, 11, 10, 9, 8, 117, 16, 15, 14, 13, 12, 11, 10, 9, 145, 18, 17, 16, 15, 14, 13, 12, 11, 10
Offset: 1

Views

Author

Gary W. Adamson, May 20 2007

Keywords

Comments

Row sums = A003215: (1, 7, 19, 37, 61, 91, ...).
Left border = A000326: (1, 5, 12, 22, 35, ...).

Examples

			First few rows of the triangle:
   1;
   5,  2;
  12,  4,  3;
  22,  6,  5,  4;
  35,  8,  7,  6, 5;
  51, 10,  9,  8, 7, 6;
  70, 12, 11, 10, 9, 8, 7;
  ...
		

Crossrefs

Formula

A051340 * A130296 as infinite lower triangular matrices.

A131034 A129686 * A051340.

Original entry on oeis.org

1, 2, 1, 4, 1, 1, 6, 2, 1, 1, 8, 2, 2, 1, 1, 10, 2, 2, 2, 1, 12, 2, 2, 2, 2, 1, 1, 14, 2, 2, 2, 2, 2, 1, 1, 16, 2, 2, 2, 2, 2, 2, 1, 1
Offset: 0

Views

Author

Gary W. Adamson, Jun 10 2007

Keywords

Comments

Row sums = A113127: (1, 3, 6, 10, 14, 18, 22, ...).

Examples

			First few rows of the triangle:
   1;
   2, 1;
   4, 1, 1;
   6, 2, 1, 1;
   8, 2, 2, 1, 1;
  10, 2, 2, 2, 1, 1;
  ...
		

Crossrefs

Formula

A129686 * A051340 as infinite lower triangular matrices.

A131228 3*A051340 - 2*A128174.

Original entry on oeis.org

1, 3, 4, 1, 3, 7, 3, 1, 3, 10, 1, 3, 1, 3, 13, 3, 1, 3, 1, 3, 16, 1, 3, 1, 3, 1, 3, 19, 3, 1, 3, 1, 3, 1, 3, 22, 1, 3, 1, 3, 1, 3, 25, 3, 1, 3, 1, 3, 1, 3, 1, 3, 28
Offset: 0

Views

Author

Gary W. Adamson, Jun 20 2007

Keywords

Comments

Row sums = A131229.

Examples

			First few rows of the triangle are:
1;
3, 4;
1, 3, 7;
3, 1, 3, 10;
1, 3, 1, 3, 13;
...
		

Crossrefs

Formula

3*A051340 - 2*A128174 as infinite lower triangular matrices.

A130265 Triangle read by rows: matrix product A007318 * A051340.

Original entry on oeis.org

1, 2, 2, 4, 5, 3, 8, 10, 10, 4, 16, 19, 23, 17, 5, 32, 36, 46, 46, 26, 6, 64, 69, 87, 102, 82, 37, 7, 128, 134, 162, 204, 204, 134, 50, 8, 256, 263, 303, 387, 443, 373, 205, 65, 9, 512, 520, 574, 718, 886, 886, 634, 298, 82, 10
Offset: 0

Views

Author

Gary W. Adamson, May 18 2007

Keywords

Examples

			First few rows of the triangle are:
   1;
   2,  2;
   4,  5,  3;
   8, 10, 10,   4;
  16, 19, 23,  17,  5;
  32, 36, 46,  46, 26,  6;
  64, 69, 87, 102, 82, 37,  7;
		

Crossrefs

Programs

  • Magma
    A130265:= func< n,k | k eq n select n+1 else (k+1)*Binomial(n,k) + (&+[Binomial(n, j+k): j in [1..n-k]]) >;
    [A130265(n,k): k in [0..n], n in [0..12]]; // G. C. Greubel, Mar 18 2023
    
  • Maple
    A051340 := proc(n,k)
        if k = n then
            n+1 ;
        elif k <= n then
            1;
        else
            0;
        end if;
    end proc:
    A130265 := proc(n,k)
        add( binomial(n,j)*A051340(j,k),j=k..n) ;
    end proc:
    seq(seq(A130265(n,k),k=0..n),n=0..15) ; # R. J. Mathar, Aug 06 2016
  • Mathematica
    T[n_, k_]:= (k+1)*Binomial[n,k] + Binomial[n,k+1]*Hypergeometric2F1[1, k-n+1, k+2, -1];
    Table[T[n, k], {n,0,12}, {k,0,n}]//Flatten (* G. C. Greubel, Mar 18 2023 *)
  • SageMath
    def A130265(n,k): return (k+1)*binomial(n,k) + sum(binomial(n, j+k) for j in range(1,n-k+1))
    flatten([[A130265(n,k) for k in range(n+1)] for n in range(13)]) # G. C. Greubel, Mar 18 2023

Formula

Binomial transform of A051340.
From G. C. Greubel, Mar 18 2023: (Start)
T(n, k) = (k+1)*binomial(n,k) + Sum_{j=1..n-k} binomial(n, j+k).
T(n, k) = (k+1)*binomial(n,k) + binomial(n,k+1)*Hypergeometric2F1([1, k-n+1], [k+2], -1).
T(2*n, n) = (1/2)*T(2*n+1, n) = A258431(n+1).
Sum_{k=0..n} T(n, k) = A001787(n+1).
Sum_{k=0..n-1} T(n, k) = A058877(n+1), for n >= 1.
Sum_{k=0..n} (-1)^k*T(n, k) = (-1)^n*A084633(n). (End)

Extensions

Missing term inserted by R. J. Mathar, Aug 06 2016

A130266 A051340 * A128174.

Original entry on oeis.org

1, 1, 2, 4, 1, 3, 2, 5, 1, 4, 7, 2, 6, 1, 5, 3, 8, 2, 7, 1, 6, 10, 3, 9, 2, 8, 1, 7, 4, 11, 3, 10, 2, 9, 1, 8, 13, 4, 12, 3, 11, 2, 10, 1, 9, 5, 14, 4, 13, 3, 12, 2, 11, 1, 10, 16, 5, 15, 4, 14, 3, 13, 2, 12, 1, 11, 6, 17, 5, 16, 4, 15, 3, 14, 2, 13
Offset: 0

Views

Author

Gary W. Adamson, May 18 2007

Keywords

Comments

Row sums = A014255: (1, 3, 8, 12, 21, 27, 40, ...).
Left border = A123684: (1, 1, 4, 2, 7, 3, 10, 4, ...).

Examples

			First few rows of the triangle:
   1;
   1, 2;
   4, 1, 3;
   2, 5, 1, 4;
   7, 2, 6, 1, 5;
   3, 8, 2, 7, 1, 6;
  10, 3, 9, 2, 8, 1, 7;
  ...
		

Crossrefs

Programs

  • Maple
    A128174 := proc(n,k)
        if k > n or k < 1 then
            0;
        else
            modp(k+n+1,2) ;
        end if;
    end proc:
    A051340 := proc(n,k)
        if k = n then
            n ;
        elif k <= n then
            1;
        else
            0;
        end if;
    end proc:
    A130266 := proc(n,k)
        add( A051340(n,j)*A128174(j,k),j=k..n) ;
    end proc:
    seq(seq(A130266(n,k),k=1..n),n=1..15) ; # R. J. Mathar, Aug 06 2016

Formula

A051340 * A128174 as infinite lower triangular matrices.
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