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.

A356150 a(n) is the sum of the positive integers whose binary expansion appears as a substring in the binary expansion of n or its complement.

Original entry on oeis.org

1, 3, 4, 10, 8, 12, 11, 25, 25, 18, 26, 28, 30, 33, 26, 56, 62, 61, 56, 56, 39, 63, 64, 67, 62, 66, 72, 77, 80, 78, 57, 119, 139, 143, 137, 135, 134, 119, 134, 134, 134, 81, 120, 138, 139, 147, 142, 146, 147, 148, 132, 153, 140, 157, 165, 165, 168, 174, 181
Offset: 1

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Author

Rémy Sigrist, Jul 28 2022

Keywords

Comments

Leading 0's in binary expansions are ignored.

Examples

			For n = 11:
- row 11 of A356149 is 1, 2, 3, 4, 5, 11,
- so a(11) = 1 + 2 + 3 + 4 + 5 + 11 = 26.
		

Crossrefs

Programs

  • PARI
    a(n) = { my (b=binary(n)); vecsum(setbinop((i,j) -> my (s=fromdigits(b[i..j],2)); if (b[i], s, 2^(j-i+1)-1-s), [1..#b])) }
    
  • Python
    def a(n):
        N = n.bit_length()
        c, s = ((1<> i)
                s.add((mask&c) >> i)
        return sum(s)
    print([a(n) for n in range(1, 60)]) # Michael S. Branicky, Jul 28 2022

Formula

a(n) >= A078823(n).
a(n) Sum_{k = 1..A356148(n)} A356149(n, k).