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.

A364955 a(n) = A252464(n) - A364954(n), where A364954(n) is the length of the common prefix in the binary expansions of A156552(n) and A156552(A163511(n)).

Original entry on oeis.org

0, 0, 0, 0, 2, 0, 1, 0, 1, 3, 4, 0, 4, 2, 2, 0, 6, 2, 7, 4, 4, 5, 8, 0, 3, 5, 3, 3, 7, 3, 6, 0, 5, 7, 4, 3, 11, 8, 6, 5, 12, 5, 13, 6, 4, 9, 14, 0, 4, 4, 6, 6, 14, 4, 4, 4, 6, 8, 14, 4, 14, 7, 3, 0, 6, 6, 18, 8, 9, 5, 19, 4, 20, 12, 3, 9, 5, 7, 21, 6, 3, 13, 22, 6, 7, 14, 10, 7, 23, 5, 6, 10, 11, 15, 8, 0, 23, 5, 5, 5
Offset: 1

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Author

Antti Karttunen, Sep 02 2023

Keywords

Crossrefs

Cf. A156552, A163511, A364954, A364956 (positions of 0's).
Cf. also A364570.

Programs

  • PARI
    Abincompreflen(n, m) = { my(x=binary(n), y=binary(m), u=min(#x, #y)); for(i=1, u, if(x[i]!=y[i], return(i-1))); (u); };
    A156552(n) = {my(f = factor(n), p, p2 = 1, res = 0); for(i = 1, #f~, p = 1 << (primepi(f[i, 1]) - 1); res += (p * p2 * (2^(f[i, 2]) - 1)); p2 <<= f[i, 2]); res}; \\ From A156552
    A163511(n) = if(!n,1,my(p=2, t=1); while(n>1, if(!(n%2), (t*=p), p=nextprime(1+p)); n >>= 1); (t*p));
    A364954(n) = Abincompreflen(A156552(n), A156552(A163511(n)));
    A061395(n) = if(n>1, primepi(vecmax(factor(n)[, 1])), 0);
    A252464(n) = if(1==n,0,(bigomega(n) + A061395(n) - 1));
    A364955(n) = (A252464(n)-A364954(n));