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 1-4 of 4 results.

A272759 a(n) = A065879(n)/n.

Original entry on oeis.org

1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 5, 2, 0, 3, 4, 1, 2, 2, 0, 2, 6, 5, 3, 2, 0, 0, 3, 3, 4, 4, 5, 1, 2, 2, 0, 2, 5, 0, 4, 2, 5, 6, 4, 5, 4, 3, 0, 2, 0, 0, 4, 0, 4, 3, 0, 3, 4, 4, 5, 4, 6, 5, 6, 1, 2, 2, 0, 2, 5, 0, 4, 2, 6, 5, 4, 0, 4, 4, 5, 2, 5, 5, 4, 6, 4, 4, 3
Offset: 1

Views

Author

Peter Kagey, May 05 2016

Keywords

Comments

This sequence is bounded above by A272756.
a(n) is the least value i such that A000120(n * i) = i or 0 if no such value exists.

Crossrefs

Programs

  • Mathematica
    Table[(SelectFirst[Range[2^12], # == n First@ DigitCount[#, 2] &] /.
        k_ /; MissingQ@ k -> 0)/n, {n, 120}] (*  *)

A272761 List of indices i such that A065879(i) != A065880(i).

Original entry on oeis.org

23, 27, 37, 41, 46, 53, 54, 57, 69, 71, 74, 77, 79, 81, 82, 83, 85, 89, 91, 92, 101, 105, 106, 107, 108, 113, 114, 121, 125, 133, 135, 138, 139, 141, 142, 143, 147, 148, 153, 154, 158, 161, 162, 163, 164, 166, 167, 169, 170, 173, 177, 178, 181, 182, 184, 197
Offset: 1

Views

Author

Peter Kagey, May 06 2016

Keywords

Comments

Equivalently a list of indices i such that A272759(i) != A272760(i).
Also, a list of indices i such that A065413(i) > 1.

Crossrefs

A065880 Largest positive number that is n times the number of 1's in its binary expansion, or 0 if no such number exists.

Original entry on oeis.org

0, 1, 2, 6, 4, 10, 12, 21, 8, 18, 20, 55, 24, 0, 42, 60, 16, 34, 36, 0, 40, 126, 110, 115, 48, 0, 0, 108, 84, 116, 120, 155, 32, 66, 68, 0, 72, 222, 0, 156, 80, 246, 252, 172, 220, 180, 230, 0, 96, 0, 0, 204, 0, 318, 216, 0, 168, 285, 232, 295, 240, 366, 310, 378, 64, 130
Offset: 0

Views

Author

Henry Bottomley, Nov 26 2001

Keywords

Comments

a(n) is bounded above by n*A272756(n), so a program only has to check values up to that point to see if a(n) is zero. - Peter Kagey, May 05 2016

Examples

			a(23)=115 since 115 is written in binary as 1110011 and 115/(1+1+1+0+0+1+1)=23 and there is no higher possibility (if k is more than 127 then k divided by its number of binary 1's is more than 26).
		

Crossrefs

A052489 is the base 10 equivalent.

Programs

  • Mathematica
    Table[SelectFirst[Reverse@ Range@ #, First@ DigitCount[#, 2] == #/n &] &[n SelectFirst[Range[2^12], # > IntegerLength[n #, 2] &]], {n, 80}] /. k_ /; MissingQ@ k -> 0 (* Michael De Vlieger, May 05 2016, Version 10.2 *)

A065878 Numbers which are not an integer multiple of their number of binary 1's.

Original entry on oeis.org

3, 5, 7, 9, 11, 13, 14, 15, 17, 19, 22, 23, 25, 26, 27, 28, 29, 30, 31, 33, 35, 37, 38, 39, 41, 43, 44, 45, 46, 47, 49, 50, 51, 52, 53, 54, 56, 57, 58, 59, 61, 62, 63, 65, 67, 70, 71, 73, 74, 75, 76, 77, 78, 79, 82, 83, 85, 86, 87, 88, 89, 90, 91, 93, 94, 95, 97, 98, 99, 100
Offset: 1

Views

Author

Henry Bottomley, Nov 26 2001

Keywords

Examples

			5 is in the sequence since 5 = 101_2 and 5 is not a multiple of 1 + 0 + 1 = 2.
		

Crossrefs

Complement of A049445.
The base-10 equivalent is A065877.

Programs

  • Mathematica
    Select[Range[100],!IntegerQ[#/Total[IntegerDigits[#,2]]]&]  (* Harvey P. Dale, Apr 20 2011 *)
  • PARI
    isok(k) = k % hammingweight(k); \\ Amiram Eldar, Aug 04 2025
Showing 1-4 of 4 results.