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 1-3 of 3 results.

A181160 Where records occur in A181159: a(n) occurs later than all positive integers k < a(n) in A181157.

Original entry on oeis.org

1, 2, 3, 5, 7, 11, 13, 18, 23, 26, 31, 36, 41, 47, 54, 58, 63, 69, 72, 76, 84, 91, 95, 99, 104, 113, 118, 126, 133, 147, 158, 167, 170, 179, 192, 206, 229, 246, 258, 273, 283, 304, 316, 339, 369, 407, 432, 444, 470, 519, 533, 561, 608, 663
Offset: 1

Views

Author

Keisuke Sato (st(AT)r3z.org), Oct 07 2010

Keywords

Extensions

a(34)-a(54) from Charlie Neder, Feb 07 2019

A306332 Records in A181159.

Original entry on oeis.org

1, 2, 6, 16, 36, 82, 166, 262, 382, 670, 766, 1066, 1492, 2050, 2470, 2710, 3370, 4192, 4432, 5050, 6274, 7354, 8050, 8590, 10270, 11256, 12250, 15190, 15670, 18910, 22666, 26026, 26110, 32146, 32230, 47806, 48250, 56026, 66652, 72766, 82630, 84706
Offset: 1

Views

Author

Charlie Neder, Feb 07 2019

Keywords

Comments

A181160 gives the indices of these terms.

Crossrefs

A181157 a(n) is the greatest integer such that the occurrence rate of integers k and above in {a(1), ..., a(n)} <= 1/k for all positive integers k.

Original entry on oeis.org

1, 2, 1, 4, 1, 3, 1, 2, 1, 10, 1, 6, 1, 2, 1, 5, 1, 3, 1, 2, 1, 22, 1, 4, 1, 2, 1, 9, 1, 3, 1, 2, 1, 8, 1, 7, 1, 2, 1, 5, 1, 3, 1, 2, 1, 46, 1, 4, 1, 2, 1, 17, 1, 3, 1, 2, 1, 14, 1, 6, 1, 2, 1, 4, 1, 3, 1, 2, 1, 35, 1, 12, 1, 2, 1, 5, 1, 3, 1, 2, 1, 11, 1, 4, 1, 2, 1, 8, 1, 3
Offset: 1

Views

Author

Keisuke Sato (st(AT)r3z.org), Oct 07 2010

Keywords

Comments

a(n) = 1 when n mod 2 = 1.
a(n) = 2 when n mod 6 = 2.
a(n) = 3 when n mod 12 = 6.
a(n) = 4 when n mod 60 = 4, 24 or 48.
a(n) = 5 when n mod 60 = 16 or 40.
Otherwise a(n) >= 6.
When we pick a term from this sequence at random, the expectation diverges to infinity.

Examples

			Let denote the occurrence rate of integers k and above in {a(1), ..., a(n)} as r(n,k). For example, r(5,2) = 2/5 since {a(1), ..., a(5)} = {1, 2, 1, 4, 1}: integers 2 and above occur twice in them.
a(6) can be 3 or above since r(6,1) = 6/6 <= 1/1, r(6,2) = 3/6 <= 1/2, and r(6,3) = 2/6 <= 1/3. But if a(6) >= 4, then r(6,4) = 2/6 > 1/4. Thus a(6) cannot be greater than 3, therefore a(6) = 3.
		

Crossrefs

Cf. A181158 (records), A181159 (first occurrence of n).

Programs

  • Mathematica
    mx = 60; acc = ConstantArray[0, mx + 1]; a = {}; Do[AppendTo[a, k = Min[Select[Range[mx], n/# - acc[[#]] < 1 &]] - 1]; acc[[Range[k]]]++, {n, mx}]; a (* Ivan Neretin, May 20 2015 *)

Extensions

a(61)-a(90) added from b-file by Charlie Neder, Feb 08 2019
Showing 1-3 of 3 results.