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.

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A139613 a(n) = 78*n + 13.

Original entry on oeis.org

13, 91, 169, 247, 325, 403, 481, 559, 637, 715, 793, 871, 949, 1027, 1105, 1183, 1261, 1339, 1417, 1495, 1573, 1651, 1729, 1807, 1885, 1963, 2041, 2119, 2197, 2275, 2353, 2431, 2509, 2587, 2665, 2743, 2821, 2899, 2977, 3055, 3133
Offset: 0

Views

Author

Omar E. Pol, Apr 27 2008

Keywords

Comments

Numbers of the 13th column of positive numbers in the square array of nonnegative and polygonal numbers A139600. Also, numbers of the 13th column in the square array A057145.

Crossrefs

Programs

Formula

From Elmo R. Oliveira, Apr 03 2024: (Start)
G.f.: 13*(1+5*x)/(x-1)^2.
E.g.f.: 13*exp(x)*(1 + 6*x).
a(n) = 13*A016921(n).
a(n) = 2*a(n-1) - a(n-2) for n >= 2. (End)

A139617 a(n) = 136*n + 17.

Original entry on oeis.org

17, 153, 289, 425, 561, 697, 833, 969, 1105, 1241, 1377, 1513, 1649, 1785, 1921, 2057, 2193, 2329, 2465, 2601, 2737, 2873, 3009, 3145, 3281, 3417, 3553, 3689, 3825, 3961, 4097, 4233, 4369, 4505, 4641, 4777, 4913, 5049, 5185, 5321
Offset: 0

Views

Author

Omar E. Pol, May 21 2008

Keywords

Comments

Numbers of the 17th column of positive numbers in the square array of nonnegative and polygonal numbers A139600. Also, numbers of the 17th column in the square array A057145.

Crossrefs

Programs

Formula

From Elmo R. Oliveira, Apr 04 2024: (Start)
G.f.: 17*(1+7*x)/(x-1)^2.
E.g.f.: 17*exp(x)*(1 + 8*x).
a(n) = 17*A017077(n).
a(n) = 2*a(n-1) - a(n-2) for n >= 2. (End)

A344410 a(n) = (3*n^2 - 1) * (3*n^2 - 2) * (3*n^3 - 3*n + 1)/2.

Original entry on oeis.org

1, 1, 1045, 23725, 195661, 975061, 3578401, 10680265, 27453385, 63016921, 132361021, 258815701, 477132085, 837244045, 1408778281, 2286380881, 3595928401, 5501691505, 8214519205, 12001111741, 17194450141, 24205450501, 33535911025, 45792819865, 61704091801
Offset: 0

Views

Author

Seiichi Manyama, May 17 2021

Keywords

Comments

a(n) is both (3*n+2)-gonal number and (3*n+2)-gonal pyramidal number.

Crossrefs

Programs

  • Mathematica
    Table[PolygonalNumber[3*n + 2, 3*n^3 - 3*n + 1], {n, 0, 24}] (* Amiram Eldar, May 17 2021 *)
    LinearRecurrence[{8,-28,56,-70,56,-28,8,-1},{1,1,1045,23725,195661,975061,3578401,10680265},30] (* Harvey P. Dale, Aug 10 2021 *)
  • PARI
    a(n) = (3*n^2-1)*(3*n^2-2)*(3*n^3-3*n+1)/2;
    
  • PARI
    p(k, n) = n*((k-2)*n-k+4)/2;
    a(n) = p(3*n+2, 3*n^3-3*n+1);
    
  • PARI
    my(N=40, x='x+O('x^N)); Vec((1-7*x+1065*x^2+15337*x^3+35135*x^4+15567*x^5+943*x^6-x^7)/(1-x)^8)

Formula

Let p(k,m) = A057145(k,m) denote m-th k-gonal number. Then
a(n) = p(3*n+2, 3*n^3-3*n+1);
a(n) = Sum_{j=1..3*n^2-2} p(3*n+2, j) for n > 0.
G.f.: (1-7*x+1065*x^2+15337*x^3+35135*x^4+15567*x^5+943*x^6-x^7)/(1-x)^8.
a(n) = 8*a(n-1) - 28*a(n-2) + 56*a(n-3) - 70*a(n-4) + 56*a(n-5) - 28*a(n-6) + 8*a(n-7) - a(n-8). - Wesley Ivan Hurt, Sep 05 2022

A350207 a(n) is the smallest positive integer which can be represented as the sum of distinct nonzero n-gonal numbers in exactly n ways, or 0 if no such integer exists.

Original entry on oeis.org

25, 65, 144, 305, 456, 622, 731, 1006, 1434, 1499, 1711, 1806, 2446, 2742, 3001, 3051, 3544, 3699, 3962, 4345, 5362, 5039, 5756, 5712, 6251, 6655, 7399, 7698, 7591, 8304, 8673, 9241, 9362, 9299, 10312, 10606, 11121, 10736, 12113, 12737, 12934
Offset: 3

Views

Author

Ilya Gutkovskiy, Dec 19 2021

Keywords

Crossrefs

A374144 a(n) is the smallest number which can be represented as the sum of two distinct nonzero n-gonal numbers in exactly n ways, or -1 if no such number exists.

Original entry on oeis.org

81, 1105, 205427, 483031, 9402323, 6232341, 79324200, 768459127, 2265692766, 2413112833, 6737406626, 150437989675, 45319359337, 15140186701
Offset: 3

Views

Author

Ilya Gutkovskiy, Jun 28 2024

Keywords

Examples

			a(3) = 81 = 3 + 78 = 15 + 66 = 36 + 45.
		

Crossrefs

Programs

  • Python
    # see linked program

Extensions

a(9)-a(16) from Michael S. Branicky, Jun 30 2024

A139607 a(n) = 21*n + 7.

Original entry on oeis.org

7, 28, 49, 70, 91, 112, 133, 154, 175, 196, 217, 238, 259, 280, 301, 322, 343, 364, 385, 406, 427, 448, 469, 490, 511, 532, 553, 574, 595, 616, 637, 658, 679, 700, 721, 742, 763, 784, 805, 826, 847, 868, 889, 910, 931, 952, 973, 994
Offset: 0

Views

Author

Omar E. Pol, Apr 27 2008

Keywords

Comments

Numbers of the 7th column of positive numbers in the square array of nonnegative and polygonal numbers A139600.
7th transversal numbers (or 7-transversal numbers): (A000217(7)-7)*n + 7.

References

  • A. H. Beiler, Recreations in the Theory of Numbers, Dover, NY, 1964, p. 189. - From N. J. A. Sloane, Dec 01 2012

Crossrefs

Programs

Formula

a(n) = A057145(n+2,7).
G.f.: 7*(1+2*x)/(x-1)^2. - R. J. Mathar, Jul 28 2016
From Elmo R. Oliveira, Apr 12 2024: (Start)
E.g.f.: 7*exp(x)*(1 + 3*x).
a(n) = 7*A016777(n) = A008603(n) + 7 = A152744(n+1) - A152744(n).
a(n) = 2*a(n-1) - a(n-2) for n >= 2. (End)

A139608 a(n) = 28*n + 8.

Original entry on oeis.org

8, 36, 64, 92, 120, 148, 176, 204, 232, 260, 288, 316, 344, 372, 400, 428, 456, 484, 512, 540, 568, 596, 624, 652, 680, 708, 736, 764, 792, 820, 848, 876, 904, 932, 960, 988, 1016, 1044, 1072, 1100, 1128, 1156, 1184, 1212, 1240, 1268, 1296, 1324, 1352, 1380
Offset: 0

Views

Author

Omar E. Pol, Apr 27 2008

Keywords

Comments

Numbers of the 8th column of positive numbers in the square array of nonnegative and polygonal numbers A139600.

References

  • A. H. Beiler, Recreations in the Theory of Numbers, Dover, NY, 1964, p. 189. - From N. J. A. Sloane, Dec 01 2012

Crossrefs

Programs

Formula

a(n) = A057145(n+2,8).
a(n) = 2*a(n-1) - a(n-2); a(0)=8, a(1)=36. - Harvey P. Dale, Dec 14 2012
G.f.: 4*(2+5*x)/(x-1)^2. - R. J. Mathar, Jul 28 2016
From Elmo R. Oliveira, Apr 16 2024: (Start)
E.g.f.: 4*exp(x)*(2 + 7*x).
a(n) = 4*A017005(n) = A135628(n) + 8 = A316466(n+1) - A316466(n). (End)

A139610 a(n) = 45*n + 10.

Original entry on oeis.org

10, 55, 100, 145, 190, 235, 280, 325, 370, 415, 460, 505, 550, 595, 640, 685, 730, 775, 820, 865, 910, 955, 1000, 1045, 1090, 1135, 1180, 1225, 1270, 1315, 1360, 1405, 1450, 1495, 1540, 1585, 1630, 1675, 1720, 1765, 1810, 1855, 1900
Offset: 0

Views

Author

Omar E. Pol, Apr 27 2008

Keywords

Comments

Numbers of the 10th column of positive numbers in the square array of nonnegative and polygonal numbers A139600.

Crossrefs

Programs

Formula

a(n) = A057145(n+2,10).
G.f.: 5*(2+7*x)/(x-1)^2. - R. J. Mathar, Jul 28 2016
From Elmo R. Oliveira, Apr 16 2024: (Start)
E.g.f.: 5*exp(x)*(2 + 9*x).
a(n) = 5*A017185(n) = 5*(A062708(n+1) - A062708(n)).
a(n) = 2*a(n-1) - a(n-2) for n >= 2. (End)

A139611 a(n) = 55*n + 11.

Original entry on oeis.org

11, 66, 121, 176, 231, 286, 341, 396, 451, 506, 561, 616, 671, 726, 781, 836, 891, 946, 1001, 1056, 1111, 1166, 1221, 1276, 1331, 1386, 1441, 1496, 1551, 1606, 1661, 1716, 1771, 1826, 1881, 1936, 1991, 2046, 2101, 2156, 2211, 2266
Offset: 0

Views

Author

Omar E. Pol, Apr 27 2008

Keywords

Comments

Numbers of the 11th column of positive numbers in the square array of nonnegative and polygonal numbers A139600.

Crossrefs

Programs

Formula

a(n) = A057145(n+2,11).
a(n) = 11 * A016861(n). - Wesley Ivan Hurt, Apr 16 2014
G.f.: 11*(1+4*x)/(x-1)^2 . - R. J. Mathar, Jul 28 2016
From Elmo R. Oliveira, Apr 16 2024: (Start)
E.g.f.: 11*exp(x)*(1 + 5*x).
a(n) = 11*(A000566(n+1) - A000566(n)).
a(n) = 2*a(n-1) - a(n-2) for n >= 2. (End)

A139612 a(n) = 66*n + 12.

Original entry on oeis.org

12, 78, 144, 210, 276, 342, 408, 474, 540, 606, 672, 738, 804, 870, 936, 1002, 1068, 1134, 1200, 1266, 1332, 1398, 1464, 1530, 1596, 1662, 1728, 1794, 1860, 1926, 1992, 2058, 2124, 2190, 2256, 2322, 2388, 2454, 2520, 2586, 2652, 2718
Offset: 0

Views

Author

Omar E. Pol, Apr 27 2008

Keywords

Comments

Numbers of the 12th column of positive numbers in the square array of nonnegative and polygonal numbers A139600. Also, numbers of the 12th column in the square array A057145.

Crossrefs

Programs

Formula

From Elmo R. Oliveira, Apr 03 2024: (Start)
G.f.: 6*(2+9*x)/(x-1)^2.
E.g.f.: 6*exp(x)*(2 + 11*x).
a(n) = 6*A017413(n).
a(n) = 2*a(n-1) - a(n-2) for n >= 2. (End)
Previous Showing 41-50 of 82 results. Next