Author: Hans Havermann
Date: 20:49:04 08/11/99
Go up one level in this thread
On August 11, 1999 at 18:45:20, I wrote:
http://www.research.att.com/cgi-bin/access.cgi/as/njas/sequences/eisA.cgi?Anum=018213
The numbers themselves are fairly easy to calculate once the definition has been
programmed (in the following, using Mathematica):
c[x_, y_] := x!/(y! (x - y)!)
d[x_, y_] := Which[
OddQ[x] && EvenQ[y], c[(x + y - 3)/2, y/2],
EvenQ[x] && EvenQ[y], c[(x + y - 4)/2, y/2],
OddQ[x] && OddQ[y], c[(x + y - 4)/2, (y - 1)/2],
EvenQ[x] && OddQ[y], 0]
l[x_, y_] := c[x + y - 3, y]/2 + d[x, y]/2
Now we can easily generate as many terms as we like (in the following, 100):
Table[l[12, n], {n, 0, 99}]
{1, 5, 30, 110, 365, 1001, 2520, 5720, 12190, 24310, 46252, 83980, 147070,
248710, 408760, 653752, 1021735, 1562275, 2343770, 3453450, 5008003, 7153575,
10080720, 14024400, 19284460, 26225628, 35304920, 47071640, 62203340, 81505820,
105959504, 136719440, 175174205, 222945905, 281963990, 354465254, 443085225,
550858165, 681329000, 838553320, 1027233130, 1252716850, 1521162500, 1839537700,
2215814250, 2658968130, 3179209800, 3787984200, 4498241475, 5324436975,
6282847506, 7391571330, 8670895455, 10143295635, 11833860640, 13770292256,
15983392920, 18507065720, 21378872240, 24640032560, 28336060632, 32516764280,
37236965920, 42556502560, 48541040185, 55262073757, 62797844110, 71233337950,
80661316645, 91182316225, 102905798008, 115950148600, 130443962870,
146526043950, 164346829660, 184068392508, 205866021270, 229928220990,
256458462040, 285675180120, 317813705759, 353126264315, 391884099530,
434377473530, 480917998715, 531838637759, 587496258800, 648271635440,
714572240900, 786832248020, 865515578760, 951115904200, 1044159966500,
1145207578900, 1254855238000, 1373736123760, 1502524020725, 1641933318025,
1792723258950, 1955697940950}
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