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.

A154203 Decimal expansion of log_10 (12).

Original entry on oeis.org

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

Views

Author

N. J. A. Sloane, Oct 30 2009

Keywords

Examples

			1.0791812460476248277225056927041013627365086271149129474507...
		

Crossrefs

Cf. decimal expansion of log_10(m): A007524 (m=2), A114490 (m=3), A114493 (m=4), A153268 (m=5), A153496 (m=6), A153620 (m=7), A153790 (m=8), A104139 (m=9), A154182 (m=11), this sequence, A154368 (m=13), A154478 (m=14), A154580 (m=15), A154794 (m=16), A154860 (m=17), A154953 (m=18), A155062 (m=19), A155522 (m=20), A155677 (m=21), A155746 (m=22), A155830 (m=23), A155979 (m=24).

Programs

Formula

Equals A007524 + A153596. - R. J. Mathar, Jan 07 2021

A166465 a(n) = 3*a(n-2) for n > 2; a(1) = 1, a(2) = 5.

Original entry on oeis.org

1, 5, 3, 15, 9, 45, 27, 135, 81, 405, 243, 1215, 729, 3645, 2187, 10935, 6561, 32805, 19683, 98415, 59049, 295245, 177147, 885735, 531441, 2657205, 1594323, 7971615, 4782969, 23914845, 14348907, 71744535, 43046721, 215233605, 129140163
Offset: 1

Views

Author

Klaus Brockhaus, Oct 14 2009

Keywords

Comments

Interleaving of A000244 and A005030.
Second binomial transform is A054485.
Fifth binomial transform is A153596.

Crossrefs

Cf. A000244 (powers of 3), A005030 (5*3^n), A054485, A153596, A162813.

Programs

  • Magma
    [ n le 2 select 4*n-3 else 3*Self(n-2): n in [1..35] ];
    
  • Mathematica
    LinearRecurrence[{0,3}, {1,5}, 41] (* G. C. Greubel, Jul 27 2024 *)
  • SageMath
    [3^(n/2)*(5*((n+1)%2) +sqrt(3)*(n%2))/3 for n in range(1,41)] # G. C. Greubel, Jul 27 2024

Formula

a(n) = (4 + (-1)^n) * 3^((2*n - 5 + (-1)^n)/4).
G.f.: x*(1+5*x)/(1-3*x^2).
a(n) = A162813(n-1), for n >= 2.
From G. C. Greubel, Jul 27 2024: (Start)
a(n) = (1/6)*3^(n/2)*( 5*(1+(-1)^n) + sqrt(3)*(1-(-1)^n) ).
E.g.f.: (1/3)*(sqrt(3)*sinh(sqrt(3)*x) + 10*(sinh(sqrt(3)*x/2))^2). (End)
Showing 1-2 of 2 results.