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.

A234016 Partial sums of the characteristic function of A055938.

Original entry on oeis.org

0, 0, 1, 1, 1, 2, 3, 3, 3, 4, 4, 4, 5, 6, 7, 7, 7, 8, 8, 8, 9, 10, 10, 10, 11, 11, 11, 12, 13, 14, 15, 15, 15, 16, 16, 16, 17, 18, 18, 18, 19, 19, 19, 20, 21, 22, 22, 22, 23, 23, 23, 24, 25, 25, 25, 26, 26, 26, 27, 28, 29, 30, 31, 31, 31, 32, 32, 32, 33, 34
Offset: 0

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Author

Antti Karttunen, Dec 18 2013

Keywords

Comments

Also: a(0) = a(1) = 0, and thereafter, a(n) = the largest k such that A055938(k) <= n.
Conjecture: partial sums of A308187 (i.e, A308187 is the characteristic function of A055938). - Sean A. Irvine, Jul 16 2022

Crossrefs

Programs

  • Python
    from sympy import factorial
    def a046699(n):
        if n<3: return 1
        s=1
        while factorial(2*s)%(2**(n - 1)): s+=1
        return s
    def a(n): return n - (a046699(n + 2) - 1)
    print([a(n) for n in range(101)]) # Indranil Ghosh, Jun 11 2017

Formula

If n < 2, a(n)=0, otherwise a(n) = a(n-1) + (1-A079559(n)).
a(n) = n - (A046699(n+2)-1) [With A046699's October 2012 starting offset].