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 1-5 of 5 results.

A171494 a(n) = 2*a(n-1) for n > 1; a(0) = 6, a(1) = 16.

Original entry on oeis.org

6, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, 131072, 262144, 524288, 1048576, 2097152, 4194304, 8388608, 16777216, 33554432, 67108864, 134217728, 268435456, 536870912, 1073741824, 2147483648
Offset: 0

Views

Author

Klaus Brockhaus, Dec 10 2009

Keywords

Comments

16*A000079 preceded by 6.
Binomial transform of A010726.
Inverse binomial transform of A171495.

Crossrefs

Equals 2*A171497.
Cf. A000079 (powers of 2), A010726 (repeat 6, 10), A171495.

Programs

  • Mathematica
    Join[{6},NestList[2#&,16,30]] (* Harvey P. Dale, Jan 13 2025 *)
  • PARI
    {m=29; v=concat([6, 16], vector(m-2)); for(n=3, m, v[n]=2*v[n-1]); v}

Formula

a(n) = 2^(n+3) for n > 0; a(0) = 6.
G.f.: 2*(3+2*x)/(1-2*x).

A171496 a(n) = 6*a(n-1) - 8*a(n-2) for n > 1; a(0) = 6, a(1) = 28.

Original entry on oeis.org

6, 28, 120, 496, 2016, 8128, 32640, 130816, 523776, 2096128, 8386560, 33550336, 134209536, 536854528, 2147450880, 8589869056, 34359607296, 137438691328, 549755289600, 2199022206976, 8796090925056, 35184367894528
Offset: 0

Views

Author

Klaus Brockhaus, Dec 10 2009

Keywords

Comments

Binomial transform of A171495; second binomial transform of A171494; third binomial transform of A010726.

Crossrefs

Programs

  • Magma
    [8*4^n-2*2^n: n in [0..30]]; // Vincenzo Librandi, Jul 18 2011
  • Mathematica
    LinearRecurrence[{6,-8},{6,28},30] (* Harvey P. Dale, Dec 21 2014 *)
  • PARI
    {m=22; v=concat([6, 28], vector(m-2)); for(n=3, m, v[n]=6*v[n-1]-8*v[n-2]); v}
    

Formula

a(n) = 8*4^n - 2*2^n.
G.f.: 2*(3-4*x)/((1-2*x)*(1-4*x)).
a(n) = A171476(n+1) = A006516(n+2).
a(n+1) - a(n) = A010036(n+2).
a(n) = 4*a(n-1)+2^(n+1) (with a(0)=6). - Vincenzo Librandi, Dec 04 2010
E.g.f.: 2*exp(2*x)*(2*exp(2*x) - 1)*(2*exp(2*x) + 1). - Stefano Spezia, Dec 10 2021

A171495 a(n) = 3*a(n-1)+4 for n > 0; a(0) = 6.

Original entry on oeis.org

6, 22, 70, 214, 646, 1942, 5830, 17494, 52486, 157462, 472390, 1417174, 4251526, 12754582, 38263750, 114791254, 344373766, 1033121302, 3099363910, 9298091734, 27894275206, 83682825622, 251048476870, 753145430614, 2259436291846
Offset: 0

Views

Author

Klaus Brockhaus, Dec 10 2009

Keywords

Comments

Binomial transform of A171494; second binomial transform of A010726.
Inverse binomial transform of A171496.

Crossrefs

Equals 2*A171498.
Cf. A010726 (repeat 6, 10), A171494, A171496.

Programs

  • Mathematica
    NestList[3#+4&,6,30] (* Harvey P. Dale, Aug 25 2019 *)
  • PARI
    {m=25; v=concat([6], vector(m-1)); for(n=2, m, v[n]=3*v[n-1]+4); v}

Formula

a(n) = 2*(4*3^n-1).
G.f.: 2*(3-x)/((1-x)*(1-3*x)).

A176403 Decimal expansion of (15+4*sqrt(15))/5.

Original entry on oeis.org

6, 0, 9, 8, 3, 8, 6, 6, 7, 6, 9, 6, 5, 9, 3, 3, 5, 0, 8, 1, 4, 3, 4, 1, 2, 3, 1, 9, 8, 2, 5, 9, 1, 9, 6, 8, 8, 6, 6, 6, 3, 3, 7, 3, 6, 4, 2, 3, 3, 2, 7, 2, 6, 6, 1, 2, 7, 0, 0, 5, 9, 0, 1, 2, 8, 9, 0, 7, 8, 6, 4, 7, 3, 5, 4, 9, 5, 8, 3, 2, 2, 6, 8, 1, 5, 4, 2, 9, 9, 0, 1, 4, 8, 6, 9, 3, 8, 8, 1, 4, 3, 3, 3, 0, 4
Offset: 1

Views

Author

Klaus Brockhaus, Apr 17 2010

Keywords

Comments

Continued fraction expansion of (15+4*sqrt(15))/5 is A010726.

Examples

			(15+4*sqrt(15))/5 = 6.09838667696593350814...
		

Crossrefs

Cf. A010472 (decimal expansion of sqrt(15)), A010726 (repeat 6, 10).

A176533 Decimal expansion of (15+4*sqrt(15))/3.

Original entry on oeis.org

1, 0, 1, 6, 3, 9, 7, 7, 7, 9, 4, 9, 4, 3, 2, 2, 2, 5, 1, 3, 5, 7, 2, 3, 5, 3, 8, 6, 6, 3, 7, 6, 5, 3, 2, 8, 1, 4, 4, 4, 3, 8, 9, 5, 6, 0, 7, 0, 5, 5, 4, 5, 4, 4, 3, 5, 4, 5, 0, 0, 9, 8, 3, 5, 4, 8, 1, 7, 9, 7, 7, 4, 5, 5, 9, 1, 5, 9, 7, 2, 0, 4, 4, 6, 9, 2, 3, 8, 3, 1, 6, 9, 1, 4, 4, 8, 9, 8, 0, 2, 3, 8, 8, 8, 4
Offset: 2

Views

Author

Klaus Brockhaus, Apr 24 2010

Keywords

Comments

Continued fraction expansion of (15+4*sqrt(15))/3 is A010726 preceded by 10.

Examples

			(15+4*sqrt(15))/3 = 10.16397779494322251357...
		

Crossrefs

Cf. A010472 (decimal expansion of sqrt(15)), A010726 (repeat 6, 10).

Programs

  • Mathematica
    RealDigits[(15+4*Sqrt[15])/3,10,120][[1]] (* Harvey P. Dale, Nov 10 2024 *)
Showing 1-5 of 5 results.