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 11-20 of 24 results. Next

A348205 Product_{n>=1} 1 / (1 - a(n)*x^n/n!) = 1 + log(1 + x).

Original entry on oeis.org

1, -3, 5, -68, 204, -1394, 16862, -413776, 2377512, -35594832, 558727872, -8067263280, 185546362416, -4108304962176, 82441247589360, -3519099528152064, 50908186083448320, -1465023121035418368, 38998680958184088960, -1219845314470474404864, 36452994894649858339584
Offset: 1

Views

Author

Ilya Gutkovskiy, Oct 06 2021

Keywords

Crossrefs

Formula

Product_{n>=1} 1 / (1 - a(n)*x^n/n!) = 1 - Sum_{n>=1} (-x)^n/n.

A348206 Product_{n>=1} (1 + a(n)*x^n/n!) = 1 + log(1 + x).

Original entry on oeis.org

1, -1, 5, -26, 204, -1434, 16862, -166536, 2377512, -29870400, 558727872, -8542202976, 185546362416, -3332732184768, 82441247589360, -1824937537167744, 50908186083448320, -1214743725939310848, 38998680958184088960, -1084067907183602910720, 36452994894649858339584
Offset: 1

Views

Author

Ilya Gutkovskiy, Oct 06 2021

Keywords

Crossrefs

Formula

Product_{n>=1} (1 + a(n)*x^n/n!) = 1 - Sum_{n>=1} (-x)^n/n.

A353818 Product_{n>=1} (1 + a(n)*x^n/n!) = 1 + arcsin(x).

Original entry on oeis.org

1, 0, 1, -4, 29, -174, 1583, -13168, 144153, -1485330, 20127867, -253341144, 3978820221, -57986205900, 1057400360235, -18016221644544, 370244721585681, -6993826454599146, 162968423791332339, -3490951922268853320, 88052648301403014789, -2075060448716599488276
Offset: 1

Views

Author

Ilya Gutkovskiy, May 08 2022

Keywords

Crossrefs

Programs

  • Mathematica
    nn = 22; f[x_] := Product[(1 + a[n] x^n/n!), {n, 1, nn}]; sol = SolveAlways[0 == Series[f[x] - 1 - ArcSin[x], {x, 0, nn}], x]; Table[a[n], {n, 1, nn}] /. sol // Flatten

A353819 Product_{n>=1} (1 + a(n)*x^n/n!) = 1 + arcsinh(x).

Original entry on oeis.org

1, 0, -1, 4, -11, 66, -547, 4880, -27351, 263310, -3258663, 39791016, -390445563, 5477278548, -84140635815, 1486404086016, -18431412645519, 322018685539542, -6436900596281679, 133183534639917240, -2208721087854287811, 49383164607876494604, -1149793471388581053219
Offset: 1

Views

Author

Ilya Gutkovskiy, May 08 2022

Keywords

Crossrefs

Programs

  • Mathematica
    nn = 23; f[x_] := Product[(1 + a[n] x^n/n!), {n, 1, nn}]; sol = SolveAlways[0 == Series[f[x] - 1 - ArcSinh[x], {x, 0, nn}], x]; Table[a[n], {n, 1, nn}] /. sol // Flatten

A353820 Product_{n>=1} (1 + a(n)*x^n/n!) = 1 + arctan(x).

Original entry on oeis.org

1, 0, -2, 8, -16, 96, -832, 9344, -27648, 238080, -4228608, 55812096, -398991360, 4930609152, -98606039040, 2440552022016, -17762113880064, 235149341884416, -7331825098948608, 170578782435409920, -2009778629489197056, 38563016760590598144, -1278044473427380666368
Offset: 1

Views

Author

Ilya Gutkovskiy, May 08 2022

Keywords

Crossrefs

Programs

  • Mathematica
    nn = 23; f[x_] := Product[(1 + a[n] x^n/n!), {n, 1, nn}]; sol = SolveAlways[0 == Series[f[x] - 1 - ArcTan[x], {x, 0, nn}], x]; Table[a[n], {n, 1, nn}] /. sol // Flatten

A353821 Product_{n>=1} (1 + a(n)*x^n/n!) = 1 + arctanh(x).

Original entry on oeis.org

1, 0, 2, -8, 64, -384, 3968, -34432, 414720, -4454400, 68247552, -912236544, 15949529088, -245572583424, 5012834549760, -92436465352704, 2119956936523776, -42836227522560000, 1123874181449515008, -26161653829651660800, 730049769522063212544, -18719979459270521389056
Offset: 1

Views

Author

Ilya Gutkovskiy, May 08 2022

Keywords

Crossrefs

Programs

  • Mathematica
    nn = 22; f[x_] := Product[(1 + a[n] x^n/n!), {n, 1, nn}]; sol = SolveAlways[0 == Series[f[x] - 1 - ArcTanh[x], {x, 0, nn}], x]; Table[a[n], {n, 1, nn}] /. sol // Flatten

A353610 Product_{n>=1} (1 + a(n)*x^(2*n)/(2*n)!) = sec(x).

Original entry on oeis.org

1, 5, -14, 1777, -14744, 247994, -74928944, 42293543177, -1163849271296, 95795966018440, -44942000161435904, 4494117864138588514, -3539995034294896016384, 770158600620174924566672, -510461123036204706738612224, 1162153458061287151457003978297
Offset: 1

Views

Author

Ilya Gutkovskiy, May 07 2022

Keywords

Crossrefs

Programs

  • Mathematica
    nn = 16; f[x_] := Product[(1 + a[n] x^(2 n)/(2 n)!), {n, 1, nn}]; sol = SolveAlways[0 == Series[f[x] - Sec[x], {x, 0, 2 nn}], x]; Table[a[n], {n, 1, nn}] /. sol // Flatten

A353779 Product_{n>=1} (1 + a(n)*x^n/n!) = 1 + tanh(x).

Original entry on oeis.org

1, 0, -2, 8, -24, 144, -720, 7552, -35840, 427520, -3628800, 45415424, -479001600, 7094226944, -82614884352, 1741160087552, -20922789888000, 371094631612416, -6402373705728000, 137529198176370688, -2379913632645120000, 55730621780175355904
Offset: 1

Views

Author

Ilya Gutkovskiy, May 08 2022

Keywords

Crossrefs

Programs

  • Mathematica
    nn = 22; f[x_] := Product[(1 + a[n] x^n/n!), {n, 1, nn}]; sol = SolveAlways[0 == Series[f[x] - 1 - Tanh[x], {x, 0, nn}], x]; Table[a[n], {n, 1, nn}] /. sol // Flatten

A006177 Witt vector *2!/2!.

Original entry on oeis.org

1, 1, 3, 8, 25, 72, 245, 772, 2692, 8925, 32065, 109890, 400023, 1402723, 5165327, 18484746, 68635477, 248339122, 930138521, 3406231198, 12810761323, 47306348881, 178987624513, 665627041157, 2528210175630, 9456885664122
Offset: 1

Views

Author

Keywords

Comments

The Somos transform sends sequence {a(n)} to sequence with g.f. Product_{i=1..n} 1/(1-a(i)*x^i).
If c is the Witt transform of b then b(n) = Sum_{d|n} A074650(n/d, c(d)).

References

  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Formula

Inverse Somos transform of A000108. - Wouter Meeussen, Aug 20 2002
Witt transform of A022553.

Extensions

Edited by Christian G. Bower, Aug 20 2002, Aug 28 2002

A353822 Product_{n>=1} (1 + x^n/n!)^a(n) = exp(-x)/(1 - x).

Original entry on oeis.org

0, 1, 2, 9, 24, 110, 720, 5985, 39200, 343224, 3628800, 41295870, 479001600, 6130959120, 87104969952, 1318070979225, 20922789888000, 354344089779680, 6402373705728000, 121882240625961816, 2432849766865689600, 51041049953430700800, 1124000727777607680000
Offset: 1

Views

Author

Ilya Gutkovskiy, May 08 2022

Keywords

Crossrefs

Programs

  • Mathematica
    nn = 23; f[x_] := Product[(1 + x^n/n!)^a[n], {n, 1, nn}]; sol = SolveAlways[0 == Series[f[x] - Exp[-x]/(1 - x), {x, 0, nn}], x]; Table[a[n], {n, 1, nn}] /. sol // Flatten
Previous Showing 11-20 of 24 results. Next