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.

A296206 Xor-Moebius transform applied twice to natural numbers.

Original entry on oeis.org

1, 2, 3, 5, 5, 6, 7, 10, 8, 10, 11, 15, 13, 14, 15, 20, 17, 16, 19, 17, 21, 22, 23, 30, 24, 26, 24, 27, 29, 30, 31, 40, 33, 34, 35, 40, 37, 38, 39, 34, 41, 42, 43, 39, 40, 46, 47, 60, 48, 48, 51, 57, 53, 48, 55, 54, 57, 58, 59, 51, 61, 62, 56, 80, 65, 66, 67, 85, 69, 70, 71, 80, 73, 74, 72, 95, 77, 78, 79, 68, 88
Offset: 1

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Author

Antti Karttunen, Dec 25 2017

Keywords

Comments

Xor-Moebius transform of A256739, in other words, the unique sequence that satisfies SumXOR_{d divides n} a(d) = A256739(n) for all n>0, where SumXOR is the analog of summation under the binary XOR operation. See A295901 for a list of some of the properties of Xor-Moebius transform.

Crossrefs

Programs

  • PARI
    A256739(n) = { if(1==n,return(n)); my(x=n); fordiv(n,d,if(dA256739(d)))); (x); };
    A296206(n) = { my(v=0); fordiv(n, d, if(issquarefree(n/d), v=bitxor(v, A256739(d)))); (v); } \\ after code in A295901.