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.

A017471 a(n) = (11*n + 6)^11.

Original entry on oeis.org

362797056, 34271896307633, 8293509467471872, 317475837322472439, 4882812500000000000, 43513917611435838661, 269561249468963094528, 1287831418538085836267, 5062982072492057196544, 17103393581163134765625
Offset: 0

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Author

Keywords

Crossrefs

Powers of the form (11*n+6)^m: A017461 (m=1), A017462 (m=2), A017463 (m=3), A017464 (m=4), A017465 (m=5), A017466 (m=6), A017467 (m=7), A017468 (m=8), A017469 (m=9), A017470 (m=10), this sequence (m=11), A017472 (m=12).

Programs

Formula

From G. C. Greubel, Sep 19 2019: (Start)
G.f.: (362797056 +34267542742961*x +7882270656385972*x^2 + 220215589053761433*x^3 +1612934439380337744*x^4 +4065965093212217778*x^5 +3893323100536505064*x^6 +1409984186533172778*x^7 +173024396961630192* x^8 +5347957556678781*x^9 +17591600106916*x^10 +48828125 x^11)/(1-x)^12.
E.g.f.: (362797056 +34271533510577*x +4112483018826831*x^2 + 48783020707697111*x^3 +152605546678854500*x^4 +184932081242538212*x^5 + 104853627173466171*x^6 +30701237124182097*x^7 +4849119426541500*x^8 + 411237867048855*x^9 +17404011907271*x^10 +285311670611*x^11)*exp(x). (End)

A017472 a(n) = (11*n + 6)^12.

Original entry on oeis.org

2176782336, 582622237229761, 232218265089212416, 12381557655576425121, 244140625000000000000, 2654348974297586158321, 19408409961765342806016, 106890007738661124410161, 475920314814253376475136, 1795856326022129150390625
Offset: 0

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Author

Keywords

Crossrefs

Powers of the form (11*n+6)^m: A017461 (m=1), A017462 (m=2), A017463 (m=3), A017464 (m=4), A017465 (m=5), A017466 (m=6), A017467 (m=7), A017468 (m=8), A017469 (m=9), A017470 (m=10), A017471 (m=11), this sequence (m=12).

Programs

Formula

From G. C. Greubel, Sep 19 2019: (Start)
G.f.: (2176782336 +582593939059393*x +224644345794247731*x^2 + 9408164121360836975*x^3 +101126771751016700469*x^4 + 380284494715132979466*x^5 +569002784856695826846*x^6 + 350628073514443644414*x^7 +85353518454518704170*x^8 + 7136462627993219301*x^9 +146435479642729343*x^10 +281471802882531*x^11 +244140625*x^12)/(1-x)^13.
E.g.f.: (2176782336 +582620060447425*x +115526511395767615*x^2 + 1947775120807282470*x^3 +8166890561727393221*x^4 + 12959517969262230432 *x^5 +9583714050157484644*x^6 +3701592580215241932*x^7 + 793530834460904067*x^8 +96520289732086275*x^9 +6542481918780841*x^10 + 227678713147578*x^11 +3138428376721*x^12)*exp(x). (End)

A076394 a(n) = p(11n+6)/11 where p(n) = number of partitions of n (A000041).

Original entry on oeis.org

1, 27, 338, 2835, 18566, 101955, 490253, 2121679, 8424520, 31120519, 108082568, 355805845, 1117485621, 3366123200, 9767105406, 27398618368, 74534264393, 197147918679, 508189847045, 1279140518117, 3149375120229, 7596463993261
Offset: 0

Views

Author

Jeff Burch, Nov 07 2002

Keywords

Comments

That p(11n+6) == 0 (mod 11) is one of the congruences stated by Ramanujan. - Omar E. Pol, Jan 18 2013

Crossrefs

Programs

  • Maple
    seq(combinat:-numbpart(11*n+6)/11, n=0..30); # Robert Israel, Jan 07 2015
  • Mathematica
    PartitionsP[(11*Range[0,30]+6)]/11 (* Harvey P. Dale, May 28 2015 *)
  • PARI
    a(n) = numbpart(11*n+6)/11; \\ Michel Marcus, Jan 07 2015

Formula

a(n) = A000041(A017461(n))/11 = A213256(n)/11. - Omar E. Pol, Jan 18 2013

A213256 p(11n+6) where p(k) = number of partitions of k = A000041(k).

Original entry on oeis.org

11, 297, 3718, 31185, 204226, 1121505, 5392783, 23338469, 92669720, 342325709, 1188908248, 3913864295, 12292341831, 37027355200, 107438159466, 301384802048, 819876908323, 2168627105469, 5590088317495, 14070545699287, 34643126322519, 83561103925871, 197726516681672, 459545750448675, 1050197489931117
Offset: 0

Views

Author

N. J. A. Sloane, Jun 07 2012

Keywords

Comments

It is known that a(n) is divisible by 11 (see A076394).

Crossrefs

Programs

  • Mathematica
    PartitionsP[11Range[0,30]+6] (* Paolo Xausa, Nov 08 2023 *)
  • PARI
    a(n) = numbpart(11*n+6); \\ Michel Marcus, Jan 07 2015

Formula

a(n) = A000041(A017461(n)). - Omar E. Pol, Jan 18 2013

A144650 Triangle read by rows where T(m,n) = 2m*n + m + n + 1.

Original entry on oeis.org

5, 8, 13, 11, 18, 25, 14, 23, 32, 41, 17, 28, 39, 50, 61, 20, 33, 46, 59, 72, 85, 23, 38, 53, 68, 83, 98, 113, 26, 43, 60, 77, 94, 111, 128, 145, 29, 48, 67, 86, 105, 124, 143, 162, 181, 32, 53, 74, 95, 116, 137, 158, 179, 200, 221, 35, 58, 81, 104, 127, 150, 173, 196, 219, 242, 265
Offset: 1

Views

Author

Vincenzo Librandi, Jan 13 2009

Keywords

Comments

First column: A016789, second column: A016885, third column: A017029, fourth column: A017221, fifth column: A017461. - Vincenzo Librandi, Nov 21 2012

Examples

			Triangle begins:
   5;
   8, 13;
  11, 18, 25;
  14, 23, 32, 41;
  17, 28, 39, 50,  61;
  20, 33, 46, 59,  72,  85;
  23, 38, 53, 68,  83,  98, 113;
  26, 43, 60, 77,  94, 111, 128, 145;
  29, 48, 67, 86, 105, 124, 143, 162, 181;
  32, 53, 74, 95, 116, 137, 158, 179, 200, 221; etc.
		

Crossrefs

Columns k: A016789 (k=1), A016885 (k=2), A017029 (k=3), A017221 (k=4), A017461 (k=5).

Programs

  • Magma
    [2*n*k + n + k + 1: k in [1..n], n in [1..11]]; // Vincenzo Librandi, Nov 21 2012
    
  • Mathematica
    T[n_,k_]:= 2 n*k + n + k + 1; Table[T[n, k], {n, 11}, {k, n}]//Flatten (* Vincenzo Librandi, Nov 21 2012 *)
  • SageMath
    flatten([[2*n*k+n+k+1 for k in range(1,n+1)] for n in range(1,13)]) # G. C. Greubel, Oct 14 2023

Formula

Sum_{n=1..m} T(m, n) = m*(2*m+3)*(m+1)/2 = A160378(n+1) (row sums). - R. J. Mathar, Jan 15 2009, Jan 05 2011
From G. C. Greubel, Oct 14 2023: (Start)
T(n, n) = A001844(n).
T(n, n-1) = A001105(n), n >= 2.
T(n, n-2) = A142463(n-1), n >= 3.
T(n, n-3) = (-1)*A147973(n+2), n >= 4.
Sum_{k=1..n} (-1)^k*T(n, k) = (-1)^n*A007742(floor((n+1)/2)).
G.f.: x*y*(5 - 2*x - 2*x*y - 2*x^2*y + x^2*y^2)/((1-x)^2*(1-x*y)^3). (End)

A141694 a(n) = 22*n + 12.

Original entry on oeis.org

12, 34, 56, 78, 100, 122, 144, 166, 188, 210, 232, 254, 276, 298, 320, 342, 364, 386, 408, 430, 452, 474, 496, 518, 540, 562, 584, 606, 628, 650, 672, 694, 716, 738, 760, 782, 804, 826, 848, 870, 892, 914, 936, 958, 980, 1002, 1024, 1046, 1068, 1090, 1112
Offset: 0

Views

Author

Paul Curtz, Sep 10 2008

Keywords

Crossrefs

Cf. A008604, A010861 (first differences), A017461.

Programs

Formula

From G. C. Greubel, Jun 03 2018: (Start)
a(n) = 2*a(n-1) - a(n-2).
G.f.: 2*(6 + 5*x)/(1 - x)^2.
E.g.f.: 2*(6 + 11*x)*exp(x). (End)
a(n) = 2*A017461(n). - Elmo R. Oliveira, Apr 11 2025

Extensions

Edited by R. J. Mathar, Oct 24 2008
Offset changed from 1 to 0 by Vincenzo Librandi, Aug 08 2011

A182719 Numbers of the form 5k + 4, 7k + 5, or 11k + 6.

Original entry on oeis.org

4, 5, 6, 9, 12, 14, 17, 19, 24, 26, 28, 29, 33, 34, 39, 40, 44, 47, 49, 50, 54, 59, 61, 64, 68, 69, 72, 74, 75, 79, 82, 83, 84, 89, 94, 96, 99, 103, 104, 105, 109, 110, 114, 116, 117, 119, 124, 127, 129, 131, 134, 138, 139, 144, 145, 149, 152, 154, 159, 160, 164
Offset: 1

Views

Author

Omar E. Pol, Feb 08 2011

Keywords

Comments

Numbers such that the Ramanujan congruences apply, making p(a(n)) divisible by at least one of 5, 7, or 11, where p is A000041.
Union of A016897, A017041 and A017461.
First differences are periodic with period length 145.

Crossrefs

Programs

  • Magma
    IsA182719:=func< n | exists{ k: k in [0..n div 5] | n in [5*k+4, 7*k+5, 11*k+6] } >; [ n: n in [1..160] | IsA182719(n) ]; // Klaus Brockhaus, Feb 08 2011
  • Mathematica
    Union[With[{no=30},Join[5Range[0,no]+4,7Range[0,no]+5,11Range[0,no]+6]]]  (* Harvey P. Dale, Feb 18 2011 *)

Formula

a(n) = a(n-145) + 385 = a(n-1) + a(n-145) - a(n-146).

Extensions

Rewritten by Charles R Greathouse IV and Klaus Brockhaus, Feb 08 2011

A304157 a(n) is the first Zagreb index of the linear phenylene G[n], defined pictorially in the Darafsheh reference.

Original entry on oeis.org

24, 68, 112, 156, 200, 244, 288, 332, 376, 420, 464, 508, 552, 596, 640, 684, 728, 772, 816, 860, 904, 948, 992, 1036, 1080, 1124, 1168, 1212, 1256, 1300, 1344, 1388, 1432, 1476, 1520, 1564, 1608, 1652, 1696, 1740, 1784, 1828, 1872, 1916, 1960, 2004, 2048
Offset: 1

Views

Author

Emeric Deutsch, May 07 2018

Keywords

Comments

The first Zagreb index of a simple connected graph is the sum of the squared degrees of its vertices. Alternatively, it is the sum of the degree sums d(i) + d(j) over all edges ij of the graph.
The M-polynomial of the linear phenylene G[n] is M(G[n];x,y) = 6*x^2*y^2 + 4*(n - 1)*x^2*y^3 + 4(n - 1)*x^3*y^3.
a(n) is the first Zagreb index of the angular phenylene shown in the Bodroza-Pantic et al. reference (Fig. 1 (b)). - Emeric Deutsch, May 24 2018

Examples

			From _Andrew Howroyd_, May 09 2018: (Start)
Illustration of the first two graphs:
       o              o         o
     /   \          /   \     /   \
    o     o        o     o---o     o
    |     |        |     |   |     |
    o     o        o     o---o     o
     \   /          \   /     \   /
       o              o         o
In general, the graph consists of a chain of n linked hexagons.
.
Case n=1: There are 6 vertices of degree 2, so a(1) = 6*2^2 = 24.
Case n=2: There are 8 vertices of degree 2 and 4 of degree 3, so a(2) = 8*2^2 + 4*3^3 = 32 + 36 = 68.
In general, there will be 2n + 4 vertices of degree 2 and 4n - 4 of degree 3.
(End)
		

Crossrefs

Programs

  • Maple
    seq(44*n - 20, n = 1 .. 40);
  • PARI
    Vec(4*x*(6 + 5*x) / (1 - x)^2 + O(x^60)) \\ Colin Barker, May 07 2018

Formula

a(n) = 44*n - 20.
a(n) = 4 * A017461(n-1).
From Colin Barker, May 07 2018: (Start)
G.f.: 4*x*(6 + 5*x) / (1 - x)^2.
a(n) = 2*a(n-1) - a(n-2) for n>2.
(End)

A330613 Triangle read by rows: T(n, k) = 1 + k - 2*n - 2*k*n + 2*n^2, with 0 <= k < n.

Original entry on oeis.org

1, 5, 2, 13, 8, 3, 25, 18, 11, 4, 41, 32, 23, 14, 5, 61, 50, 39, 28, 17, 6, 85, 72, 59, 46, 33, 20, 7, 113, 98, 83, 68, 53, 38, 23, 8, 145, 128, 111, 94, 77, 60, 43, 26, 9, 181, 162, 143, 124, 105, 86, 67, 48, 29, 10, 221, 200, 179, 158, 137, 116, 95, 74, 53, 32, 11
Offset: 1

Views

Author

Stefano Spezia, Dec 20 2019

Keywords

Comments

T(n, k) is the k-th super- and subdiagonal sum of the matrix M(n) whose permanent is A330287(n).

Examples

			n\k|   0   1   2   3   4   5
---+------------------------
1  |   1
2  |   5   2
3  |  13   8   3
4  |  25  18  11   4
5  |  41  32  23  14   5
6  |  61  50  39  28  17   6
...
For n = 3 the matrix M is
      1, 2, 3
      2, 4, 6
      3, 6, 8
and therefore T(3, 0) = 1 + 4 + 8 = 13, T(3, 1) = 2 + 6 = 8 and T(3, 2) = 3.
		

Crossrefs

Cf. A000027: diagonal; A001105: 2nd column; A001844: 1st column; A016789: 1st subdiagonal; A016885: 2nd subdiagonal; A017029: 3rd subdiagonal; A017221: 4th subdiagonal; A017461: 5th subdiagonal; A081436: row sums; A132209: 3rd column; A164284: 7th subdiagonal; A269044: 6th subdiagonal.

Programs

  • Mathematica
    Flatten[Table[1+k-2n-2k*n+2n^2,{n,1,11},{k,0,n-1}]] (* or *)
    r[n_] := Table[SeriesCoefficient[(1-x*(2-5x+2(1+x)y))/((1-x)^3*(1-y)^2), {x, 0, i}, {y, 0, j}], {i, n, n}, {j, 0, n-1}]; Flatten[Array[r, 11]] (* or *)
    r[n_] := Table[SeriesCoefficient[Exp[x+y]*(1+2x(x-y)+y), {x, 0, i}, {y, 0, j}]*i!*j!, {i, n, n}, {j, 0, n-1}]; Flatten[Array[r, 11]]

Formula

O.g.f.: (1 - x*(2 - 5*x + 2*(1 + x)*y))/((1 - x)^3*(1 - y)^2).
E.g.f.: exp(x+y)*(1 + 2*x*(x - y) + y).
T(n, k) = A001844(n-1) - k*A005408(n-1), with 0 <= k < n. [Typo corrected by Stefano Spezia, Feb 14 2020]
Previous Showing 11-19 of 19 results.