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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A116454 Smallest m such that A116452(m) = n.

Original entry on oeis.org

0, 2, 9, 25, 59, 129, 271, 557, 1131, 2281, 4583, 9189, 18403, 36833, 73695, 147421, 294875, 589785, 1179607, 2359253, 4718547, 9437137, 18874319, 37748685, 75497419, 150994889, 301989831, 603979717, 1207959491, 2415919041
Offset: 1

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Author

Reinhard Zumkeller, Feb 16 2006

Keywords

Comments

A116451(a(n)) = A116453(n);
Primes include a(2) = 2, a(5) = 59, a(7) = 271, a(8) = 557, a(10) = 2281, a(11) = 4583, a(14) = 36833. - Jonathan Vos Post, Feb 20 2006

Programs

  • Mathematica
    Join[{0},RecurrenceTable[{a[1]==2,a[n]==2(a[n-1]+n)+1},a[n],{n,30}]] (* or *) Join[{0},LinearRecurrence[{4,-5,2},{2,9,25},30]] (* Harvey P. Dale, Jul 18 2011 *)

Formula

a(n+1) = (a(n) + n) * 2 + 1 for n>1.
From Harvey P. Dale, Jul 18 2011: (Start)
a(0)=0, a(1)=2, a(2)=9, a(3)=25, a(n) = 4*a(n-1)-5*a(n-2)+2*a(n-3).
G.f.: (x-2)*x^2*(x+1)/((x-1)^2*(2*x-1)). (End)

A116451 Numbers having fewer prime factors than at least one smaller number.

Original entry on oeis.org

5, 7, 9, 10, 11, 13, 14, 15, 17, 18, 19, 20, 21, 22, 23, 25, 26, 27, 28, 29, 30, 31, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82
Offset: 0

Views

Author

Reinhard Zumkeller, Feb 16 2006

Keywords

Comments

Complement of A029744.
Numbers whose odd part is greater than 3. - Peter Munn, Aug 12 2020

Crossrefs

Formula

A116452(n) = A001222(a(n)).

Extensions

The offset should really be 1, since this is a list, but that change would also require a complete rewrite of A116454, plus changes to A116453. So for the moment let's leave this with offset 0. - N. J. A. Sloane, Aug 17 2020
Showing 1-2 of 2 results.