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 41-50 of 94 results. Next

A010974 a(n) = binomial(n,21).

Original entry on oeis.org

1, 22, 253, 2024, 12650, 65780, 296010, 1184040, 4292145, 14307150, 44352165, 129024480, 354817320, 927983760, 2319959400, 5567902560, 12875774670, 28781143380, 62359143990, 131282408400, 269128937220, 538257874440, 1052049481860, 2012616400080, 3773655750150
Offset: 21

Views

Author

Keywords

Comments

In this sequence there are no primes. - Artur Jasinski, Dec 02 2007

Crossrefs

Pascal's triangle A007318. - Zerinvary Lajos, Aug 04 2008

Programs

Formula

a(n) = n*(n+1)*(n+2)*(n+3)*(n+4)*(n+5)*(n+6)*(n+7)*(n+8)*(n+9)*(n+10)*(n+11)*(n+12)*(n+13)*(n+14)*(n+15)*(n+16)*(n+17)*(n+18)*(n+19)*(n+20) / 21!. - Artur Jasinski, Dec 02 2007
a(n) = n/(n-21) * a(n-1), n > 21. - Vincenzo Librandi, Mar 26 2011
From Amiram Eldar, Dec 11 2020: (Start)
Sum_{n>=21} 1/a(n) = 21/20.
Sum_{n>=21} (-1)^(n+1)/a(n) = A001787(21)*log(2) - A242091(21)/20! = 22020096*log(2) - 42299423848079/2771340 = 0.9580705153... (End)

A010976 Binomial coefficient C(n,23).

Original entry on oeis.org

1, 24, 300, 2600, 17550, 98280, 475020, 2035800, 7888725, 28048800, 92561040, 286097760, 834451800, 2310789600, 6107086800, 15471286560, 37711260990, 88732378800, 202112640600, 446775310800, 960566918220, 2012616400080, 4116715363800, 8233430727600
Offset: 23

Views

Author

Keywords

Crossrefs

Pascal's triangle A007318. [Zerinvary Lajos, Aug 04 2008]

Programs

Formula

a(n) = n/(n-23) * a(n-1) for n > 23. - Vincenzo Librandi, Mar 26 2011
G.f.: x^23/(1-x)^24. - G. C. Greubel, Nov 23 2017
From Amiram Eldar, Dec 11 2020: (Start)
Sum_{n>=23} 1/a(n) = 23/22.
Sum_{n>=23} (-1)^(n+1)/a(n) = A001787(23)*log(2) - A242091(23)/22! = 96468992*log(2) - 1945773591174209/29099070 = 0.9613305695... (End)

A010977 a(n) = binomial coefficient C(n,24).

Original entry on oeis.org

1, 25, 325, 2925, 20475, 118755, 593775, 2629575, 10518300, 38567100, 131128140, 417225900, 1251677700, 3562467300, 9669554100, 25140840660, 62852101650, 151584480450, 353697121050, 800472431850, 1761039350070, 3773655750150, 7890371113950, 16123801841550
Offset: 24

Views

Author

Keywords

Crossrefs

Pascal's triangle A007318 diagonal. - Zerinvary Lajos, Aug 04 2008

Programs

Formula

G.f.: x^24/(1-x)^25. - Zerinvary Lajos, Aug 04 2008 [Corrected by Georg Fischer, May 19 2019]
a(n) = n/(n-24) * a(n-1), n > 24. - Vincenzo Librandi, Mar 26 2011
From Amiram Eldar, Dec 11 2020: (Start)
Sum_{n>=24} 1/a(n) = 24/23.
Sum_{n>=24} (-1)^n/a(n) = A001787(24)*log(2) - A242091(24)/23! = 201326592*log(2) - 15566188845789952/111546435 = 0.9627768409... (End)

A010995 Binomial coefficient C(n,42).

Original entry on oeis.org

1, 43, 946, 14190, 163185, 1533939, 12271512, 85900584, 536878650, 3042312350, 15820024220, 76223753060, 343006888770, 1451182990950, 5804731963800, 22057981462440, 79960182801345, 277508869722315, 925029565741050, 2969831763694950, 9206478467454345
Offset: 42

Views

Author

Keywords

Comments

Coordination sequence for 42-dimensional cyclotomic lattice Z[zeta_43].

Crossrefs

Programs

Formula

G.f.: x^42/(1-x)^43. - Zerinvary Lajos, Dec 20 2008
From Amiram Eldar, Dec 15 2020: (Start)
Sum_{n>=42} 1/a(n) = 42/41.
Sum_{n>=42} (-1)^n/a(n) = A001787(42)*log(2) - A242091(42)/41! = 92358976733184*log(2) - 41737723319039140166101476641/651964850415450 = 0.9777363438... (End)

A017717 Binomial coefficients C(n,53).

Original entry on oeis.org

1, 54, 1485, 27720, 395010, 4582116, 45057474, 386206920, 2944827765, 20286591270, 127805525001, 743595781824, 4027810484880, 20448884000160, 97862516286480, 443643407165376, 1913212193400684, 7877932561061640
Offset: 53

Views

Author

Keywords

Crossrefs

Programs

Formula

From G. C. Greubel, Nov 03 2018: (Start)
G.f.: x^53/(1-x)^54.
E.g.f.: x^53*exp(x)/53!. (End)
From Amiram Eldar, Dec 16 2020: (Start)
Sum_{n>=53} 1/a(n) = 53/52.
Sum_{n>=53} (-1)^(n+1)/a(n) = A001787(53)*log(2) - A242091(53)/52! = 238690780250636288*log(2) - 12818255587371480560673756439003166003 / 77476112606149917660 = 0.9821211403... (End)

A017719 Binomial coefficients C(n,55).

Original entry on oeis.org

1, 56, 1596, 30856, 455126, 5461512, 55525372, 491796152, 3872894697, 27540584512, 179013799328, 1074082795968, 5996962277488, 31368725759168, 154603005527328, 721480692460864, 3201570572795084, 13559593014190944
Offset: 55

Views

Author

Keywords

Crossrefs

Programs

Formula

From G. C. Greubel, Nov 03 2018: (Start)
G.f.: x^55/(1-x)^56.
E.g.f.: x^55*exp(x)/55!. (End)
From Amiram Eldar, Dec 16 2020: (Start)
Sum_{n>=55} 1/a(n) = 55/54.
Sum_{n>=55} (-1)^(n+1)/a(n) = A001787(55)*log(2) - A242091(55)/54! = 990791918021509120*log(2) - 25636511174742961236844310374211301851 / 37329399710235869418 = 0.9827390452... (End)

A017764 a(n) = binomial coefficient C(n,100).

Original entry on oeis.org

1, 101, 5151, 176851, 4598126, 96560646, 1705904746, 26075972546, 352025629371, 4263421511271, 46897636623981, 473239787751081, 4416904685676756, 38393094575497956, 312629484400483356, 2396826047070372396, 17376988841260199871, 119594570260437846171
Offset: 100

Views

Author

Keywords

Comments

More generally, the ordinary generating function for the binomial coefficients C(n,k) is x^k/(1 - x)^(k+1). - Ilya Gutkovskiy, Mar 21 2016

Crossrefs

Cf. similar sequences of the binomial coefficients C(n,k): A000012 (k = 0), A001477 (k = 1), A000217 (k = 2), A000292 (k = 3), A000332 (k = 4), A000389 (k = 5), A000579-A000582 (k = 6..9) A001287 (k = 10), A001288 (k = 11), A010965-A011001 (k = 12..48), A017713-A017763 (k = 49..99), this sequence (k = 100).

Programs

Formula

G.f.: x^100/(1 - x)^101. - Ilya Gutkovskiy, Mar 21 2016
E.g.f.: x^100 * exp(x)/(100)!. - G. C. Greubel, Nov 24 2017
From Amiram Eldar, Dec 20 2020: (Start)
Sum_{n>=100} 1/a(n) = 100/99.
Sum_{n>=100} (-1)^n/a(n) = A001787(100)*log(2) - A242091(100)/99! = 63382530011411470074835160268800*log(2) - 1914409165727592211172313915606932788039791776845041612575266508424929 / 43575234518570298227833630584570189723 = 0.9902877001... (End)

A010973 a(n) = binomial(n,20).

Original entry on oeis.org

1, 21, 231, 1771, 10626, 53130, 230230, 888030, 3108105, 10015005, 30045015, 84672315, 225792840, 573166440, 1391975640, 3247943160, 7307872110, 15905368710, 33578000610, 68923264410, 137846528820, 269128937220, 513791607420, 960566918220, 1761039350070
Offset: 20

Views

Author

Keywords

Comments

In this sequence there are no primes. - Artur Jasinski, Dec 02 2007

Crossrefs

Pascal's triangle A007318 diagonal. - Zerinvary Lajos, Aug 04 2008

Programs

Formula

a(n+19) = n*(n+1)*(n+2)*(n+3)*(n+4)*(n+5)*(n+6)*(n+7)*(n+8)*(n+9)*(n+10)*(n+11)*(n+12)*(n+13)*(n+14)*(n+15)*(n+16)*(n+17)*(n+18)*(n+19)/20!. - Artur Jasinski, Dec 02 2007; R. J. Mathar, Jul 07 2009
G.f.: x^20/(1-x)^21. - Zerinvary Lajos, Aug 04 2008; R. J. Mathar, Jul 07 2009
a(n) = n/(n-20) * a(n-1), n > 20. - Vincenzo Librandi, Mar 26 2011
From Amiram Eldar, Dec 11 2020: (Start)
Sum_{n>=20} 1/a(n) = 20/19.
Sum_{n>=20} (-1)^n/a(n) = A001787(20)*log(2) - A242091(20)/19! = 10485760*log(2) - 21149710469086/2909907 = 0.9562240549... (End)

Extensions

Some formulas adjusted to the offset by R. J. Mathar, Jul 07 2009

A010975 a(n) = binomial(n,22).

Original entry on oeis.org

1, 23, 276, 2300, 14950, 80730, 376740, 1560780, 5852925, 20160075, 64512240, 193536720, 548354040, 1476337800, 3796297200, 9364199760, 22239974430, 51021117810, 113380261800, 244662670200, 513791607420, 1052049481860, 2104098963720, 4116715363800
Offset: 22

Views

Author

Keywords

Comments

Coordination sequence for 22-dimensional cyclotomic lattice Z[zeta_23].

Crossrefs

Pascal's triangle A007318. - Zerinvary Lajos, Aug 04 2008

Programs

Formula

a(n) = n/(n-22) * a(n-1), n > 22. - Vincenzo Librandi, Mar 26 2011
G.f.: x^22/(1-x)^23. - G. C. Greubel, Nov 23 2017
From Amiram Eldar, Dec 11 2020: (Start)
Sum_{n>=22} 1/a(n) = 22/21.
Sum_{n>=22} (-1)^n/a(n) = A001787(22)*log(2) - A242091(22)/21! = 46137344*log(2) - 42299425233749/1322685 = 0.9597667941... (End)

A010978 a(n) = binomial(n,25).

Original entry on oeis.org

1, 26, 351, 3276, 23751, 142506, 736281, 3365856, 13884156, 52451256, 183579396, 600805296, 1852482996, 5414950296, 15084504396, 40225345056, 103077446706, 254661927156, 608359048206, 1408831480056, 3169870830126, 6943526580276, 14833897694226, 30957699535776
Offset: 25

Views

Author

Keywords

Crossrefs

Programs

Formula

From Zerinvary Lajos, Aug 18 2008: (Start)
a(n) = C(n,25), n >= 25.
G.f.: x^25/(1-x)^26. (End) [G.f. corrected by Georg Fischer, May 19 2019]
From Amiram Eldar, Dec 11 2020: (Start)
Sum_{n>=25} 1/a(n) = 25/24.
Sum_{n>=25} (-1)^(n+1)/a(n) = A001787(25)*log(2) - A242091(25)/24! = 419430400*log(2) - 155661889015631695/535422888 = 0.9641184185... (End)
Previous Showing 41-50 of 94 results. Next