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.

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A153043 Numbers n > 1 such that 2*n-3 is not a prime.

Original entry on oeis.org

2, 6, 9, 12, 14, 15, 18, 19, 21, 24, 26, 27, 29, 30, 33, 34, 36, 39, 40, 42, 44, 45, 47, 48, 49, 51, 54, 57, 59, 60, 61, 62, 63, 64, 66, 68, 69, 72, 73, 74, 75, 78, 79, 81, 82, 84, 86, 87, 89, 90, 93, 94, 95, 96, 99, 102, 103, 104, 105, 106, 108, 109, 110
Offset: 1

Views

Author

Vincenzo Librandi, Dec 17 2008

Keywords

Comments

One more than the associated value in A104275. - R. J. Mathar, Jan 05 2011
2*A155705(m,n)-3 = (2n+1)*(2m+1) are nonprime: all A155705(.,.) are in this sequence.
The terms after a(1) are the values of 2*h*k + k + h + 2, where h and k are positive integers. - Vincenzo Librandi, Jan 19 2013

Links

Crossrefs

Cf. A098090, A104275, A153040, A155705.

Programs

A162267 a(n) = (2*n^3 + 5*n^2 + 5*n)/2.

Original entry on oeis.org

6, 23, 57, 114, 200, 321, 483, 692, 954, 1275, 1661, 2118, 2652, 3269, 3975, 4776, 5678, 6687, 7809, 9050, 10416, 11913, 13547, 15324, 17250, 19331, 21573, 23982, 26564, 29325, 32271, 35408, 38742, 42279, 46025, 49986, 54168, 58577, 63219
Offset: 1

Views

Author

Vincenzo Librandi, Jun 29 2009

Keywords

Links

Crossrefs

Cf. A155705.

Programs

  • Mathematica
    LinearRecurrence[{4, -6, 4, -1}, {6, 23, 57, 114}, 50] (* or *) CoefficientList[Series[(6-x+x^2)/(1-x)^4,{x,0,40}],x] (* Vincenzo Librandi, Mar 05 2012 *)

Formula

Row sums from A155705: a(n) = Sum_{m=1..n} (2*m*n + m + n + 2).
From Vincenzo Librandi, Mar 05 2012: (Start)
G.f.: x*(6 - x + x^2)/(1-x)^4.
a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4). (End)

Extensions

New name from Vincenzo Librandi, Mar 05 2012
Showing 1-2 of 2 results.

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