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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A065560 a(n) is the smallest integer k such that floor((1+1/n)^(k+1))/floor((1+1/n)^k) = 1+1/n.

Original entry on oeis.org

2, 4, 7, 9, 12, 15, 18, 21, 25, 28, 40, 35, 39, 42, 46, 50, 54, 58, 62, 66, 70, 74, 78, 83, 87, 91, 95, 100, 104, 109, 113, 118, 122, 127, 131, 136, 141, 145, 150, 155, 159, 164, 169, 174, 179, 183, 188, 193, 198, 203, 208, 213, 218, 223, 228, 233, 238, 243, 248, 253
Offset: 2

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Author

Benoit Cloitre, Nov 29 2001

Keywords

Comments

a(n) is growing roughly like prime(n). a(n) < a(n+1) except for n = 12. (Is this the only exception?)
a(n) < a(n+1) except for n = 12, 108, 266, ... - Boris Gourevitch (boris(AT)pi314.net), Dec 04 2001
Conjecture: a(n)+n > prime(n).

Examples

			a(5) = 9 because 9 is the first integer satisfying floor((6/5)^(9+1))/floor((6/5)^9) = 6/5.
		

Crossrefs

Programs

  • PARI
    a(n) = { my(k=1, f=(n + 1)/n); while((floor(f^(k + 1))/floor(f^k)) != f, k++); k } \\ Harry J. Smith, Oct 22 2009

Formula

Asymptotic (conjectured) formula: a(n)=n*log(n)+o(log(n)).

Extensions

Terms a(53) - a(61) from Harry J. Smith, Oct 22 2009

A081723 Let b(n)=floor((3/2)^n), c(n)=floor((4/3)^n); sequence gives values of n such that b(n+1)/b(n)=3/2 and c(n+1)/c(n)=4/3.

Original entry on oeis.org

13, 24, 49, 67, 79, 88, 102, 126, 132, 162, 172, 194, 199, 204, 217, 234, 253, 255, 261, 271, 297, 320, 325, 328, 338, 351, 365, 377, 403, 411, 414, 462, 477, 482, 525, 533, 537, 541, 567, 569, 579, 601, 613, 638, 706, 740, 749, 761, 762, 773, 804, 809, 817
Offset: 1

Views

Author

Benoit Cloitre, Apr 06 2003

Keywords

Crossrefs

Formula

It seems that a(n) is asymptotic to C*n where 12<=C<=13

A081724 Let b(n)=floor((3/2)^n), c(n)=floor((4/3)^n), d(n)=floor((5/4)^n); sequence gives values of n such that b(n+1)/b(n)=3/2, c(n+1)/c(n)=4/3 and d(n+1)/d(n)=5/4.

Original entry on oeis.org

162, 172, 204, 328, 403, 414, 809, 835, 840, 854, 1111, 1117, 1160, 1188, 1192, 1270, 1294, 1311, 1351, 1409, 1469, 1478, 1508, 1605, 1614, 1769, 1842, 1961, 2065, 2226, 2425, 2456, 2460, 2486, 2581, 2597, 2635, 2638, 2642, 2650, 2679, 2720, 2880, 2932
Offset: 1

Views

Author

Benoit Cloitre, Apr 06 2003

Keywords

Crossrefs

Programs

  • Mathematica
    bcdQ[n_]:=Module[{b=Floor[(3/2)^n],b1=Floor[(3/2)^(n+1)],c=Floor[ (4/3)^n], c1=Floor[(4/3)^(n+1)],d=Floor[(5/4)^n],d1=Floor[(5/4)^(n+1)]}, b1/b==3/2&&c1/c==4/3&&d1/d==5/4]; Select[Range[3000],bcdQ] (* Harvey P. Dale, Jun 08 2013 *)

Formula

It seems that a(n) is asymptotic to C*n where C is around 60.
Showing 1-3 of 3 results.