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 1-2 of 2 results.

A164095 a(n) = 2*a(n-2) for n > 2; a(1) = 5, a(2) = 6.

Original entry on oeis.org

5, 6, 10, 12, 20, 24, 40, 48, 80, 96, 160, 192, 320, 384, 640, 768, 1280, 1536, 2560, 3072, 5120, 6144, 10240, 12288, 20480, 24576, 40960, 49152, 81920, 98304, 163840, 196608, 327680, 393216, 655360, 786432, 1310720, 1572864, 2621440, 3145728
Offset: 1

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Author

Klaus Brockhaus, Aug 10 2009

Keywords

Comments

Interleaving of A020714 and A007283 without initial term 3.
Partial sums are in A164096.
Binomial transform is A048655 without initial 1, second binomial transform is A161941 without initial 2, third binomial transform is A164037, fourth binomial transform is A161731 without initial 1, fifth binomial transform is A164038, sixth binomial transform is A164110.

Crossrefs

Programs

  • Magma
    [ n le 2 select n+4 else 2*Self(n-2): n in [1..40] ];
  • Mathematica
    LinearRecurrence[{0,2},{5,6},50] (* or *) With[{nn=20},Riffle[NestList[ 2#&,5,nn],NestList[2#&,6,nn]]] (* Harvey P. Dale, Aug 15 2020 *)

Formula

a(n) = A070876(n)/3.
a(n) = (4-(-1)^n)*2^(1/4*(2*n-1+(-1)^n)).
G.f.: x*(5+6*x)/(1-2*x^2).

A304517 a(n) = 16*2^n - 11 (n>=1).

Original entry on oeis.org

21, 53, 117, 245, 501, 1013, 2037, 4085, 8181, 16373, 32757, 65525, 131061, 262133, 524277, 1048565, 2097141, 4194293, 8388597, 16777205, 33554421, 67108853, 134217717, 268435445, 536870901, 1073741813, 2147483637, 4294967285, 8589934581, 17179869173, 34359738357, 68719476725, 137438953461, 274877906933, 549755813877
Offset: 1

Views

Author

Emeric Deutsch, May 15 2018

Keywords

Comments

a(n) is the number of edges of the nanostar dendrimer NS2[n] from the Madanshekaf et al. reference.

Crossrefs

First bisection of A164096 without 5. First column of the table in A224701.

Programs

  • GAP
    List([1..40],n->16*2^n-11); # Muniru A Asiru, May 15 2018
    
  • Maple
    seq(16*2^n-11, n = 1 .. 40);
  • Mathematica
    Rest@ CoefficientList[Series[x (21 - 10 x)/((1 - x) (1 - 2 x)), {x, 0, 35}], x] (* or *)
    LinearRecurrence[{3, -2}, {21, 53}, 35] (* or *)
    Array[16*2^# - 11 &, 35] (* Michael De Vlieger, May 15 2018 *)
  • PARI
    Vec(x*(21 - 10*x) / ((1 - x)*(1 - 2*x)) + O(x^40)) \\ Colin Barker, May 15 2018

Formula

From Colin Barker, May 15 2018: (Start)
G.f.: x*(21 - 10*x) / ((1 - x)*(1 - 2*x)).
a(n) = 3*a(n-1) - 2*a(n-2) for n>2.
(End)
Showing 1-2 of 2 results.