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.

Showing 1-10 of 16 results. Next

A324712 Xor-Moebius transform of A323243, where A323243(n) = sigma(A156552(n)).

Original entry on oeis.org

0, 1, 3, 5, 7, 4, 15, 12, 15, 11, 31, 15, 63, 28, 22, 16, 127, 7, 255, 28, 43, 46, 511, 24, 27, 106, 20, 39, 1023, 60, 2047, 56, 42, 206, 34, 44, 4095, 508, 172, 32, 8191, 24, 16383, 113, 57, 734, 32767, 56, 51, 9, 128, 213, 65535, 4, 67, 116, 748, 1768, 131071, 26, 262143, 3406, 20, 72, 70, 125, 524287, 389, 762, 22
Offset: 1

Views

Author

Antti Karttunen, Mar 12 2019

Keywords

Comments

Properties of Xor-Moebius transform are explained in A295901.

Crossrefs

Programs

  • PARI
    A324712(n) = { my(v=0); fordiv(n, d, if(issquarefree(n/d), v=bitxor(v, A323243(d)))); (v); } \\ For A323243, see under that entry.

Formula

a(n) = A297106(n) XOR A324714(n).
a(A000040(n)) = A000225(n).

A256739 Unique sequence satisfying SumXOR_{d divides n} a(d) = n for any n>0, where SumXOR is the analog of summation under the binary XOR operation.

Original entry on oeis.org

1, 3, 2, 6, 4, 6, 6, 12, 10, 12, 10, 12, 12, 10, 8, 24, 16, 30, 18, 24, 16, 30, 22, 24, 28, 20, 18, 20, 28, 24, 30, 48, 40, 48, 32, 60, 36, 54, 40, 48, 40, 48, 42, 60, 40, 58, 46, 48, 54, 36, 32, 40, 52, 54, 56, 40, 40, 36, 58, 48, 60, 34, 32, 96, 72, 120, 66
Offset: 1

Views

Author

Paul Tek, Apr 09 2015

Keywords

Comments

Replacing "SumXOR" by "Sum" in the name leads to the Euler totient function (A000010).
Replacing "SumXOR" by "Product" in the name leads to the exponential of Mangoldt function (A014963).
a(p) = p-1 for any prime p>2.
a(2^k) = 2^k+2^(k-1) for any k>0.
A070939(a(n)) = A070939(n) for any n>0.
The graph of this sequence is quite remarkable. - N. J. A. Sloane, Apr 09 2015
Xor-Moebius transform of natural numbers, A000027. See A295901 for a list of some of the properties of this transform. - Antti Karttunen, Dec 29 2017

Crossrefs

Programs

  • Mathematica
    a = Table[0, {16383}];
    Do[pa = n; Do[pa = BitXor[pa, a[[d]]], {d, Divisors[n]}]; a[[n]] = pa, {n, Length[a]}];
    a (* Jean-François Alcover, Oct 18 2019, after Paul Tek *)
  • PARI
    \\ See Links section.
    
  • PARI
    A256739(n) = { my(v=0); fordiv(n, d, if(issquarefree(n/d), v=bitxor(v, d))); (v); } \\ Antti Karttunen, Dec 29 2017, after code in A295901.

Formula

a(n) = n XOR ( SumXOR_{d divides n and d < n} a(d) ) for any n>0.
From Antti Karttunen, Dec 29 2017: (Start)
a(n) = SumXOR_{d|n} A296206(d).
a(n) = n XOR A296207(n), where XOR is bitwise exclusive or, A003987.
(End)

A297106 Xor-Moebius transform of A156552.

Original entry on oeis.org

0, 1, 2, 2, 4, 6, 8, 4, 4, 12, 16, 12, 32, 24, 12, 8, 64, 12, 128, 24, 24, 48, 256, 24, 8, 96, 8, 48, 512, 20, 1024, 16, 48, 192, 24, 24, 2048, 384, 96, 48, 4096, 40, 8192, 96, 24, 768, 16384, 48, 16, 24, 192, 192, 32768, 24, 48, 96, 384, 1536, 65536, 40, 131072, 3072, 48, 32, 96, 80, 262144, 384, 768, 40, 524288, 48
Offset: 1

Views

Author

Antti Karttunen, Dec 25 2017

Keywords

Comments

Unique sequence satisfying SumXOR_{d divides n} a(d) = A156552(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 the Xor-Moebius transform.
The ordinary Möbius transform of A156552 is given in A297112.
It seems that A091629 gives the fixed points of this sequence.

Crossrefs

Programs

  • PARI
    A064989(n) = {my(f); f = factor(n); if((n>1 && f[1,1]==2), f[1,2] = 0); for (i=1, #f~, f[i,1] = precprime(f[i,1]-1)); factorback(f)};
    A156552(n) = if(1==n, 0, if(!(n%2), 1+(2*A156552(n/2)), 2*A156552(A064989(n))));
    A297106(n) = { my(v=0); fordiv(n, d, if(issquarefree(n/d), v=bitxor(v, A156552(d)))); (v); } \\ after code in A295901.

A297108 If n is prime(k)^e, e >= 1, then a(n) = 2^(k-1), otherwise 0; Möbius transform of A048675.

Original entry on oeis.org

0, 1, 2, 1, 4, 0, 8, 1, 2, 0, 16, 0, 32, 0, 0, 1, 64, 0, 128, 0, 0, 0, 256, 0, 4, 0, 2, 0, 512, 0, 1024, 1, 0, 0, 0, 0, 2048, 0, 0, 0, 4096, 0, 8192, 0, 0, 0, 16384, 0, 8, 0, 0, 0, 32768, 0, 0, 0, 0, 0, 65536, 0, 131072, 0, 0, 1, 0, 0, 262144, 0, 0, 0, 524288, 0, 1048576, 0, 0, 0, 0, 0, 2097152, 0, 2, 0, 4194304
Offset: 1

Views

Author

Antti Karttunen, Dec 25 2017

Keywords

Comments

This is also Xor-Moebius transform of A248663, in other words, the unique sequence satisfying SumXOR_{d divides n} a(d) = A248663(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 this transform.

Crossrefs

Programs

  • PARI
    A297108(n) = if(1==omega(n),2^(primepi(factor(n)[1,1])-1),0);
    \\ A more complicated way which demonstrates the Moebius transform:
    A048675(n) = { my(f = factor(n)); sum(k=1, #f~, f[k, 2]*2^primepi(f[k, 1]))/2; }; \\ This function after Michel Marcus
    A297108(n) = sumdiv(n,d,moebius(n/d)*A048675(d));
    \\ And yet another way demonstrating the comment:
    A248663(n) = A048675(core(n));
    A297108(n) = { my(v=0); fordiv(n, d, if(issquarefree(n/d), v=bitxor(v, A248663(d)))); (v); } \\ after code in A295901.

Formula

If A001221(n) = 1 [when n is in A000961], then a(n) = 2^(A297109(n)-1) = 2^(A055396(n)-1), otherwise 0.
a(n) = Sum_{d|n} A048675(d)*A008683(n/d).

A296203 Xor-Moebius transform of A000203, the sum of divisors.

Original entry on oeis.org

1, 2, 5, 4, 7, 10, 9, 8, 9, 22, 13, 20, 15, 18, 27, 16, 19, 34, 21, 60, 45, 42, 25, 40, 25, 38, 37, 36, 31, 78, 33, 32, 57, 38, 63, 108, 39, 42, 51, 120, 43, 90, 45, 116, 95, 82, 49, 80, 49, 86, 95, 76, 55, 122, 67, 72, 65, 70, 61, 204, 63, 66, 65, 64, 93, 130, 69, 76, 125, 166, 73, 184, 75, 86, 125, 180, 101, 190, 81, 240, 81
Offset: 1

Views

Author

Antti Karttunen, Dec 25 2017, from Rémy Sigrist's "gallery of scatter plots" in A295901

Keywords

Comments

Unique sequence satisfying SumXOR_{d divides n} a(d) = sigma(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
    A296203(n) = { my(v=0); fordiv(n, d, if(issquarefree(n/d), v=bitxor(v, sigma(d)))); (v); } \\ after code in A295901.

A296207 Xor-Moebius transform of A227320, binary XOR of proper divisors of n.

Original entry on oeis.org

0, 1, 1, 2, 1, 0, 1, 4, 3, 6, 1, 0, 1, 4, 7, 8, 1, 12, 1, 12, 5, 8, 1, 0, 5, 14, 9, 8, 1, 6, 1, 16, 9, 18, 3, 24, 1, 16, 15, 24, 1, 26, 1, 16, 5, 20, 1, 0, 7, 22, 19, 28, 1, 0, 15, 16, 17, 30, 1, 12, 1, 28, 31, 32, 9, 58, 1, 36, 21, 38, 1, 48, 1, 38, 19, 32, 13, 54, 1, 48, 27, 42, 1, 52, 21, 40, 31, 32, 1, 34, 11, 40, 29, 44, 23, 0, 1
Offset: 1

Views

Author

Antti Karttunen, Dec 25 2017

Keywords

Comments

Unique sequence satisfying SumXOR_{d divides n} a(d) = A227320(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

Cf. A297107 (positions of zeros).

Programs

  • PARI
    A227320(n) = { my(s=0); fordiv(n,d,if(dA296207(n) = { my(v=0); fordiv(n, d, if(issquarefree(n/d), v=bitxor(v, A227320(d)))); (v); } \\ after code in A295901.

Formula

a(n) = n XOR A256739(n), where XOR is the bitwise XOR-operation (A003987).

A324714 a(n) = A297106(n) XOR A324712(n).

Original entry on oeis.org

0, 0, 1, 7, 3, 2, 7, 8, 11, 7, 15, 3, 31, 4, 26, 24, 63, 11, 127, 4, 51, 30, 255, 0, 19, 10, 28, 23, 511, 40, 1023, 40, 26, 14, 58, 52, 2047, 124, 204, 16, 4095, 48, 8191, 17, 33, 478, 16383, 8, 35, 17, 64, 21, 32767, 28, 115, 20, 876, 232, 65535, 50, 131071, 334, 36, 104, 38, 45, 262143, 5, 506, 62, 524287, 68, 1048575, 1786, 59
Offset: 1

Views

Author

Antti Karttunen, Mar 13 2019

Keywords

Comments

a(n) is also the XOR-Moebius transform of (A156552(d) XOR A323243(d)). See A295901 for the properties of that transform.

Crossrefs

Programs

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

Views

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.

A296208 Xor-Moebius transform of A005187.

Original entry on oeis.org

1, 2, 5, 4, 9, 12, 10, 8, 20, 24, 18, 24, 22, 16, 23, 16, 33, 60, 34, 48, 41, 56, 43, 48, 39, 36, 34, 40, 55, 52, 56, 32, 86, 96, 65, 120, 70, 104, 88, 96, 78, 104, 83, 120, 88, 112, 88, 96, 84, 84, 71, 80, 103, 104, 115, 80, 72, 68, 112, 96, 116, 76, 75, 64, 158, 244, 130, 192, 168, 192, 139, 240, 142, 212, 175, 216
Offset: 1

Views

Author

Antti Karttunen, Dec 25 2017

Keywords

Comments

Unique sequence satisfying SumXOR_{d divides n} a(d) = A005187(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. A297111 gives the ordinary Möbius transform of A005187.

Crossrefs

Programs

  • PARI
    A005187(n) = { my(s=n); while(n>>=1, s+=n); s; };
    A296208(n) = { my(v=0); fordiv(n, d, if(issquarefree(n/d), v=bitxor(v, A005187(d)))); (v); } \\ after code in A295901.

A297110 Xor-Moebius transform of A006068, inverse of the binary Gray code.

Original entry on oeis.org

1, 2, 3, 4, 7, 4, 4, 8, 12, 8, 12, 8, 8, 12, 15, 16, 31, 20, 28, 16, 31, 20, 27, 16, 23, 24, 28, 24, 23, 16, 20, 32, 48, 32, 63, 40, 56, 36, 48, 32, 48, 32, 51, 40, 48, 44, 52, 32, 36, 56, 63, 48, 39, 36, 47, 48, 48, 56, 44, 32, 40, 60, 63, 64, 112, 80, 124, 64, 96, 64, 123, 80, 112, 72, 111, 72, 127, 80, 116, 64
Offset: 1

Views

Author

Antti Karttunen, Dec 25 2017

Keywords

Comments

Unique sequence satisfying SumXOR_{d divides n} a(d) = A006068(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 the Xor-Moebius transform.

Crossrefs

Programs

  • PARI
    A006068(n)= { my(s=1, ns); while(1, ns = n >> s; if(0==ns, break()); n = bitxor(n, ns); s <<= 1; ); return (n); } \\ Essentially Joerg Arndt's Jul 19 2012 code.
    A297110(n) = { my(v=0); fordiv(n, d, if(issquarefree(n/d), v=bitxor(v, A006068(d)))); (v); };
Showing 1-10 of 16 results. Next