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 1-7 of 7 results.

A285407 G.f.: 1/(1 - x^2/(1 - x^3/(1 - x^5/(1 - x^7/(1 - x^11/(1 - ... - x^prime(k)/(1 - ... ))))))), a continued fraction.

Original entry on oeis.org

1, 0, 1, 0, 1, 1, 1, 2, 2, 3, 5, 5, 9, 11, 15, 23, 28, 43, 57, 78, 113, 149, 214, 293, 403, 569, 774, 1086, 1502, 2072, 2896, 3986, 5548, 7691, 10636, 14797, 20459, 28400, 39386, 54542, 75724, 104886, 145468, 201733, 279545, 387786, 537472, 745233, 1033383, 1432415, 1986394
Offset: 0

Views

Author

Ilya Gutkovskiy, Apr 18 2017

Keywords

Examples

			G.f.: A(x) = 1 + x^2 + x^4 + x^5 + x^6 + 2*x^7 + 2*x^8 + 3*x^9 + 5*x^10 + ...
		

Crossrefs

Programs

  • Maple
    R:= 1:
    for i from numtheory:-pi(50) to 1 by -1 do
      R:= series(1-x^ithprime(i)/R, x, 51);
    od:
    R:= series(1/R, x, 51):
    seq(coeff(R,x,j),j=0..50); # Robert Israel, Apr 20 2017
  • Mathematica
    nmax = 50; CoefficientList[Series[1/(1 + ContinuedFractionK[-x^Prime[k], 1, {k, 1, nmax}]), {x, 0, nmax}], x]

Formula

a(n) ~ c * d^n, where d = 1.3864622092472465020397266918102624708859968795203700659786636158522760956... and c = 0.15945087310540003725148530084775272562567007586487061850065597143186... - Vaclav Kotesovec, Aug 25 2017

A206740 G.f.: 1/(1 - x/(1 - x^3/(1 - x^6/(1 - x^10/(1 - x^15/(1 - x^21/(1 -...- x^(n*(n+1)/2)/(1 -...))))))), a continued fraction.

Original entry on oeis.org

1, 1, 1, 1, 2, 3, 4, 6, 9, 13, 20, 30, 44, 66, 99, 147, 220, 329, 490, 732, 1095, 1634, 2440, 3646, 5444, 8130, 12146, 18139, 27089, 40463, 60434, 90258, 134811, 201349, 300721, 449153, 670844, 1001939, 1496467, 2235080, 3338227, 4985868, 7446739, 11122179
Offset: 0

Views

Author

Paul D. Hanna, Feb 12 2012

Keywords

Examples

			G.f.: A(x) = 1 + x + x^2 + x^3 + 2*x^4 + 3*x^5 + 4*x^6 + 6*x^7 + 9*x^8 +...
		

Crossrefs

Cf. A206739.

Programs

  • Mathematica
    nmax = 50; CoefficientList[Series[1/Fold[(1 - #2/#1) &, 1, Reverse[x^(Range[nmax + 1]*(Range[nmax + 1] + 1)/2)]], {x, 0, nmax}], x] (* Vaclav Kotesovec, Aug 24 2017 *)
  • PARI
    {a(n)=local(CF=1+x*O(x^n),M=sqrtint(n+1)); for(k=0, M, CF=1/(1-x^((M-k+1)*(M-k+2)/2)*CF)); polcoeff(CF, n, x)}
    for(n=0,55,print1(a(n),", "))

Formula

G.f.: 1/Q(0) , where Q(k) = 1 - x^((2*k+1)*(2*k+2)/2)/(1 - x^((2*k+2)*(2*k+3)/2)/Q(k+1) ); (continued fraction). - Sergei N. Gladkovskii, Sep 10 2013
a(n) ~ c * d^n, where d = 1.49356638691558702616975760297981328... and c = 0.35853801643147450974166770910994348... - Vaclav Kotesovec, Aug 24 2017

A285408 Expansion of 1/(1 + x/(1 + x^4/(1 + x^9/(1 + x^16/(1 + x^25/(1 + ... + x^(k^2)/(1 + ...))))))), a continued fraction.

Original entry on oeis.org

1, -1, 1, -1, 1, 0, -1, 2, -3, 3, -2, 0, 3, -6, 7, -6, 2, 5, -12, 17, -17, 9, 6, -24, 40, -45, 32, -1, -44, 89, -112, 97, -34, -72, 189, -272, 273, -153, -84, 380, -637, 723, -526, 22, 703, -1427, 1824, -1593, 575, 1126, -3041, 4423, -4461, 2562, 1251, -6096
Offset: 0

Views

Author

Ilya Gutkovskiy, Apr 18 2017

Keywords

Examples

			G.f.: A(x) = 1 - x + x^2 - x^3 + x^4 - x^6 + 2*x^7 - 3*x^8 + 3*x^9 - 2*x^10 +  ...
		

Crossrefs

Programs

  • Mathematica
    nmax = 55; CoefficientList[Series[1/(1 + ContinuedFractionK[x^k^2, 1, {k, 1, nmax}]), {x, 0, nmax}], x]

A290771 Square array A(n,k), n >= 0, k >= 0, read by antidiagonals, where column k is the expansion of the continued fraction 1/(1 - x/(1 - x^(2^k)/(1 - x^(3^k)/(1 - x^(4^k)/(1 - x^(5^k)/(1 - ...)))))).

Original entry on oeis.org

1, 1, 1, 1, 1, 2, 1, 1, 1, 5, 1, 1, 1, 2, 14, 1, 1, 1, 1, 3, 42, 1, 1, 1, 1, 1, 5, 132, 1, 1, 1, 1, 1, 2, 9, 429, 1, 1, 1, 1, 1, 1, 3, 15, 1430, 1, 1, 1, 1, 1, 1, 1, 4, 26, 4862, 1, 1, 1, 1, 1, 1, 1, 1, 5, 45, 16796, 1, 1, 1, 1, 1, 1, 1, 1, 1, 7, 78, 58786, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 10, 135, 208012
Offset: 0

Views

Author

Ilya Gutkovskiy, Aug 10 2017

Keywords

Examples

			Square array begins:
   1,  1,  1,  1,  1,  1, ...
   1,  1,  1,  1,  1,  1, ...
   2,  1,  1,  1,  1,  1, ...
   5,  2,  1,  1,  1,  1, ...
  14,  3,  1,  1,  1,  1, ...
  42,  5,  2,  1,  1,  1, ...
		

Crossrefs

Columns k = 0..5 give A000108, A005169, A206739, A291146, A291149, A291168.

Programs

  • Mathematica
    Table[Function[k, SeriesCoefficient[1/(1 + ContinuedFractionK[-x^(i^k), 1, {i, 1, n}]), {x, 0, n}]][j - n], {j, 0, 12}, {n, 0, j}] // Flatten

Formula

G.f. of column k: 1/(1 - x/(1 - x^(2^k)/(1 - x^(3^k)/(1 - x^(4^k)/(1 - x^(5^k)/(1 - ...)))))), a continued fraction.

A290975 Expansion of 1 - x/(1 - x^4/(1 - x^9/(1 - x^16/(1 - x^25/(1 - x^36/(1 - ... - x^(n^2)/(1 - ...))))))), a continued fraction.

Original entry on oeis.org

1, -1, 0, 0, 0, -1, 0, 0, 0, -1, 0, 0, 0, -1, -1, 0, 0, -1, -2, 0, 0, -1, -3, -1, 0, -1, -4, -3, 0, -1, -6, -6, -1, -1, -8, -10, -4, -1, -10, -17, -10, -2, -12, -27, -20, -6, -15, -40, -38, -16, -19, -56, -68, -36, -27, -79, -114, -75, -45, -109, -180, -147, -84
Offset: 0

Views

Author

Seiichi Manyama, Aug 16 2017

Keywords

Examples

			G.f. = 1 - x - x^5 - x^9 - x^13 - x^14 - x^17 - 2*x^18 - ...
		

Crossrefs

Cf. A206739.

Formula

Convolution inverse of A206739.

A291146 Expansion of 1/(1 - x/(1 - x^8/(1 - x^27/(1 - x^64/(1 - x^125/(1 - x^216/(1 - ... - x^(n^3)/(1 - ...)))))))), a continued fraction.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 14, 18, 23, 29, 36, 44, 53, 64, 78, 96, 119, 148, 184, 228, 281, 345, 423, 519, 639, 788, 973, 1202, 1484, 1830, 2254, 2774, 3415, 4206, 5183, 6390, 7880, 9717, 11979, 14762, 18188, 22408, 27609, 34022, 41931
Offset: 0

Views

Author

Seiichi Manyama, Aug 18 2017

Keywords

Examples

			G.f. = 1 + x + x^2 + x^3 + x^4 + x^5 + x^6 + x^7 + x^8 + 2*x^9 + 3*x^10 + 4*x^11 + 5*x^12 + ...
		

Crossrefs

Column k=3 of A290771.

A295073 Expansion of 1/(1 - x/(1 - x^5/(1 - x^14/(1 - x^30/(1 - x^55/(1 - ... - x^(k*(k+1)*(2*k+1)/6)/(1 - ...))))))), a continued fraction.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 2, 3, 4, 5, 6, 8, 11, 15, 20, 26, 34, 45, 60, 80, 107, 142, 188, 249, 330, 439, 584, 776, 1030, 1366, 1813, 2408, 3199, 4249, 5642, 7490, 9944, 13204, 17534, 23285, 30920, 41056, 54514, 72384, 96116, 127631, 169478, 225042, 298819, 396783, 526869, 699608, 928981, 1233552
Offset: 0

Views

Author

Ilya Gutkovskiy, Nov 13 2017

Keywords

Crossrefs

Programs

  • Mathematica
    nmax = 53; CoefficientList[Series[1/(1 + ContinuedFractionK[-x^(k (k + 1) (2 k + 1)/6), 1, {k, 1, nmax}]), {x, 0, nmax}], x]

Formula

G.f.: 1/(1 - x/(1 - x^5/(1 - x^14/(1 - x^30/(1 - x^55/(1 - ... - x^A000330(k)/(1 - ...))))))), a continued fraction.
a(n) ~ c * d^n, where d = 1.327852426419013789340602526081665378868516025761586390361772232517175463... and c = 0.366619510178622647108505347089605503045273798338613615745637268621... - Vaclav Kotesovec, Sep 18 2021
Showing 1-7 of 7 results.