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.

A047131 a(n) = Sum_{i=0..n} A047130(i, n-i).

Original entry on oeis.org

1, 2, 3, 6, 10, 20, 35, 70, 140, 252, 504, 932, 1864, 3493, 6986, 13972, 26265, 52530, 100168, 200336, 384573, 769146, 1538292, 2950530, 5901060, 11422700, 22845400, 44403564, 88807128, 177614256, 344644881, 689289762, 1346117062
Offset: 0

Views

Author

Keywords

Crossrefs

Cf. A047130.

Programs

  • PARI
    A(h, k=h)={my(M=matrix(h+1, k+1, i, j, 1)); for(h=1, h, for(k=1, k, M[1+h, 1+k] = M[h, 1+k] + if(4*k>3*h && 4*(k-1)<3*h, 0, M[1+h, k]))); M}
    seq(n)={my(T=A(n)); vector(#T, k, sum(i=0, k-1, T[1+i, k-i]))} \\ Andrew Howroyd, Jan 19 2020

Extensions

Definition corrected and edited by Georg Fischer, Jan 19 2020

A047132 T(n,n), array T as in A047130.

Original entry on oeis.org

1, 1, 2, 5, 28, 84, 272, 911, 3885, 14049, 50891, 185464, 735146, 2794719, 10565837, 39940553, 155711860, 601589056, 2317413464, 8920255482, 34742183340, 135196049411, 525683426601, 2043377119966, 7980296279061
Offset: 0

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Author

Keywords

Extensions

Definition corrected by Georg Fischer, Jan 20 2020

A047133 T(n,n-1), array T as in A047130.

Original entry on oeis.org

1, 2, 5, 14, 28, 84, 272, 1679, 5564, 19613, 70504, 311534, 1172750, 4405073, 16581264, 67108040, 260573610, 1004778126, 3867996120, 15289911196, 59854486782, 233437968413, 909025875014, 3575067252387, 14038457059264
Offset: 1

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Author

Keywords

Extensions

Definition corrected by Georg Fischer, Jan 20 2020

A047134 T(n,n-2), array T as in A047130.

Original entry on oeis.org

1, 3, 9, 28, 76, 235, 768, 1679, 5564, 19613, 126070, 437604, 1610354, 6015427, 27167487, 104861750, 403189070, 1550582656, 6369655714, 25112303442, 98241919002, 383342448413, 1531690132421, 6058160780203, 23859853900666
Offset: 2

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Author

Keywords

Extensions

Definition corrected by Georg Fischer, Jan 20 2020

A047135 a(n) = T(n,n-3), array T as in A047130.

Original entry on oeis.org

1, 4, 14, 48, 151, 496, 1679, 4892, 16099, 55566, 126070, 437604, 1610354, 10586223, 37753710, 142615460, 545804530, 2501659594, 9822392246, 38387432220, 149904480000, 622664257407, 2483093527816, 9821396841402
Offset: 3

Views

Author

Keywords

Crossrefs

Cf. A047130.

Extensions

Definition corrected by Georg Fischer, Jan 20 2020

A047136 a(n) = T(n,n+1), array T as in A047130.

Original entry on oeis.org

1, 2, 5, 14, 56, 188, 639, 2206, 8485, 31278, 114960, 423612, 1621969, 6160764, 23359289, 88603820, 341015446, 1312635338, 5052259362, 19452272144, 75341562629, 292245458188, 1134351244952, 4405229026674, 17153557736343
Offset: 0

Views

Author

Keywords

Crossrefs

Cf. A047130.

Extensions

Definition corrected by Georg Fischer, Jan 20 2020

A047137 a(n) = T(n,n+2), array T as in A047130.

Original entry on oeis.org

1, 3, 9, 28, 104, 367, 1295, 4600, 17229, 64069, 238148, 886823, 3366045, 12793452, 48663267, 185303586, 711046282, 2734845898, 10532016662, 40599379289, 157049408777, 608667818351, 2361851906708, 9173261457282
Offset: 0

Views

Author

Keywords

Crossrefs

Cf. A047130.

Extensions

Definition corrected by Georg Fischer, Jan 20 2020

A047138 a(n) = T(n,n+3), array T as in A047130.

Original entry on oeis.org

1, 4, 14, 48, 179, 656, 2394, 8744, 32791, 123188, 463211, 1744076, 6632688, 25303978, 96699766, 370030836, 1422210560, 5479757300, 21147107145, 81707846148, 316422360163, 1227500661756, 4768032430608, 18539704936398
Offset: 0

Views

Author

Keywords

Crossrefs

Cf. A047130.

Extensions

Definition corrected by Georg Fischer, Jan 20 2020

A047139 T(2n,n), array T as in A047130.

Original entry on oeis.org

1, 2, 9, 48, 261, 1534, 9319, 56808, 353362, 2227380, 14099553, 89931668, 577292621, 3718701300, 24047442913, 156059054586, 1015345651345, 6621929417524, 43283675452318, 283439130488986, 1859169844171611
Offset: 0

Views

Author

Clark Kimberling. Definition revised Dec 08 2006

Keywords

A047140 Array read by diagonals: T(h,k)=number of paths consisting of steps from (0,0) to (h,k) such that each step has length 1 directed up or right and no up-step crosses the line y=4x/3. (Thus a path crosses the line only at lattice points and on right-steps.).

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 1, 3, 1, 1, 2, 4, 4, 1, 1, 3, 2, 8, 5, 1, 1, 4, 5, 10, 13, 6, 1, 1, 5, 9, 15, 23, 19, 7, 1, 1, 6, 14, 24, 38, 42, 26, 8, 1, 1, 7, 20, 38, 62, 80, 68, 34, 9, 1, 1, 8, 27, 58, 38, 142, 148, 102, 43, 10, 1, 1, 9, 35, 85, 96, 180, 290
Offset: 0

Views

Author

Clark Kimberling. Definition revised Dec 08 2006

Keywords

Examples

			Array begins:
======================================
h\k | 0 1  2   3   4   5    6    7
----+---------------------------------
  0 | 1 1  1   1   1   1    1    1 ...
  1 | 1 2  1   2   3   4    5    6 ...
  2 | 1 3  4   2   5   9   14   20 ...
  3 | 1 4  8  10  15  24   38   58 ...
  4 | 1 5 13  23  38  62   38   96 ...
  5 | 1 6 19  42  80 142  180   96 ...
  6 | 1 7 26  68 148 290  470  566 ...
  7 | 1 8 34 102 250 540 1010 1576 ...
  ...
		

Crossrefs

Programs

  • PARI
    A(h,k=h)={my(M=matrix(h+1,k+1,i,j,1)); for(h=1, h, for(k=1, k, M[1+h, 1+k] = M[h,1+k] + if(3*k>4*h && 3*(k-1)<4*h, 0, M[1+h,k]))); M}
    { my(T=A(10)); for(i=1, #T, print(T[i,]))} \\ Andrew Howroyd, Jan 19 2020
Showing 1-10 of 10 results.