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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A232245 Sum of the number of ones in binary representation of n and n^2.

Original entry on oeis.org

0, 2, 2, 4, 2, 5, 4, 6, 2, 5, 5, 8, 4, 7, 6, 8, 2, 5, 5, 8, 5, 9, 8, 7, 4, 8, 7, 10, 6, 9, 8, 10, 2, 5, 5, 8, 5, 9, 8, 11, 5, 8, 9, 11, 8, 12, 7, 9, 4, 8, 8, 9, 7, 12, 10, 12, 6, 10, 9, 12, 8, 11, 10, 12, 2, 5, 5, 8, 5, 9, 8, 11, 5, 9, 9, 13, 8, 11, 11, 10, 5, 9
Offset: 0

Views

Author

Jon Perry, Nov 20 2013

Keywords

Comments

The sequence is never 1 or 3, but seems to take on all other values. The fact it is never 3 can be used to prove if n^2 has exactly 4 1's then it must have an even number of 0's (A231898).

Examples

			5 is 101 and 25 is 11001, so a(5) = 2 + 3 = 5.

Crossrefs

Cf. A000120, A159918, A077436, A094694, A231898, A232243.

Programs

  • JavaScript
    function bitCount(n) {
var i,c,s;
c=0;
s=n.toString(2);
for (i=0;i

Formula

a(n) = A159918(n) + A000120(n).
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Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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