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 1-4 of 4 results.

A238801 Triangle T(n,k), read by rows, given by T(n,k) = C(n+1, k+1)*(1-(k mod 2)).

Original entry on oeis.org

1, 2, 0, 3, 0, 1, 4, 0, 4, 0, 5, 0, 10, 0, 1, 6, 0, 20, 0, 6, 0, 7, 0, 35, 0, 21, 0, 1, 8, 0, 56, 0, 56, 0, 8, 0, 9, 0, 84, 0, 126, 0, 36, 0, 1, 10, 0, 120, 0, 252, 0, 120, 0, 10, 0, 11, 0, 165, 0, 462, 0, 330, 0, 55, 0, 1, 12, 0, 220, 0, 792, 0, 792, 0, 220, 0, 12, 0
Offset: 0

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Author

Philippe Deléham, Mar 05 2014

Keywords

Comments

Row sums are powers of 2.

Examples

			Triangle begins:
1;
2, 0;
3, 0, 1;
4, 0, 4, 0;
5, 0, 10, 0, 1;
6, 0, 20, 0, 6, 0;
7, 0, 35, 0, 21, 0, 1;
8, 0, 56, 0, 56, 0, 8, 0;
9, 0, 84, 0, 126, 0, 36, 0, 1;
10, 0, 120, 0, 252, 0, 120, 0, 10, 0; etc.
		

Crossrefs

Programs

  • Mathematica
    Table[Binomial[n + 1, k + 1]*(1 - Mod[k , 2]), {n, 0, 10}, {k, 0, n}] // Flatten (* G. C. Greubel, Nov 22 2017 *)
  • PARI
    T(n,k) = binomial(n+1, k+1)*(1-(k % 2));
    tabl(nn) = for (n=0, nn, for (k=0, n, print1(T(n,k), ", ")); print); \\ Michel Marcus, Nov 23 2017

Formula

G.f.: 1/((1+(y-1)*x)*(1-(y+1)*x)).
T(n,k) = 2*T(n-1,k) + T(n-2,k-2) - T(n-2,k), T(0,0) = 1, T(1,0) = 2, T(1,1) = 0, T(n,k) = 0 if k<0 or if k>n.
Sum_{k=0..n} T(n,k)*x^k = A000027(n+1), A000079(n), A015518(n+1), A003683(n+1), A079773(n+1), A051958(n+1), A080920(n+1), A053455(n), A160958(n+1) for x = 0, 1, 2, 3, 4, 5, 6, 7, 8 respectively.

A017760 Binomial coefficients C(n,96).

Original entry on oeis.org

1, 97, 4753, 156849, 3921225, 79208745, 1346548665, 19813501785, 257575523205, 3005047770725, 31853506369685, 309847743777845, 2788629694000605, 23381587434312765, 183712472698171725, 1359472297966470765, 9516306085765295355, 63255446334792845595
Offset: 96

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Keywords

Crossrefs

Programs

Formula

From G. C. Greubel, Nov 12 2018: (Start)
G.f.: x^96/(1-x)^97.
E.g.f.: x^96*exp(x)/96!. (End)
From Amiram Eldar, Dec 20 2020: (Start)
Sum_{n>=96} 1/a(n) = 96/95.
Sum_{n>=96} (-1)^n/a(n) = A001787(96)*log(2) - A242091(96)/95! = 3802951800684688204490109616128*log(2) - 9868088483131918614290277915496170231743780878869426700864981897216 / 3743576848674424246377459672213933825 = 0.9898949826... (End)

A017758 Binomial coefficients C(n,94).

Original entry on oeis.org

1, 95, 4560, 147440, 3612280, 71523144, 1192052400, 17199613200, 219295068300, 2509710226100, 26100986351440, 249145778809200, 2200787712814600, 18114175790089400, 139737927523546800, 1015428940004440080, 6981073962530525550, 45582306461228725650
Offset: 94

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Keywords

Crossrefs

Programs

Formula

From G. C. Greubel, Nov 12 2018: (Start)
G.f.: x^94/(1-x)^95.
E.g.f.: x^94*exp(x)/94!. (End)
From Amiram Eldar, Dec 20 2020: (Start)
Sum_{n>=94} 1/a(n) = 94/93.
Sum_{n>=94} (-1)^n/a(n) = A001787(94)*log(2) - A242091(94)/93! = 930930909542605966724141416448*log(2) - 154188882548936228348285592429449074905987023631107827159541306779 / 238951713745176015726220830141314925 = 0.9896864636... (End)

A017759 Binomial coefficients C(n,95).

Original entry on oeis.org

1, 96, 4656, 152096, 3764376, 75287520, 1267339920, 18466953120, 237762021420, 2747472247520, 28848458598960, 277994237408160, 2478781950222760, 20592957740312160, 160330885263858960, 1175759825268299040, 8156833787798824590, 53739140249027550240
Offset: 95

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Author

Keywords

Crossrefs

Programs

Formula

From G. C. Greubel, Nov 12 2018: (Start)
G.f.: x^95/(1-x)^96.
E.g.f.: x^95*exp(x)/95!. (End)
From Amiram Eldar, Dec 20 2020: (Start)
Sum_{n>=95} 1/a(n) = 95/94.
Sum_{n>=95} (-1)^(n+1)/a(n) = A001787(95)*log(2) - A242091(95)/94! = 1881668859713778017846668820480*log(2) - 308377765097872456696571184859137101525719223277941875149223928483 / 236436432547858373455418505613511610 = 0.9897917882... (End)
Showing 1-4 of 4 results.