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.

Previous Showing 11-20 of 25 results. Next

A297168 Difference between A156552 and its Moebius transform: a(n) = A156552(n) - A297112(n).

Original entry on oeis.org

0, 0, 0, 1, 0, 3, 0, 3, 2, 5, 0, 7, 0, 9, 6, 7, 0, 9, 0, 11, 10, 17, 0, 15, 4, 33, 6, 19, 0, 17, 0, 15, 18, 65, 12, 19, 0, 129, 34, 23, 0, 29, 0, 35, 14, 257, 0, 31, 8, 17, 66, 67, 0, 21, 20, 39, 130, 513, 0, 35, 0, 1025, 22, 31, 36, 53, 0, 131, 258, 33, 0, 39, 0, 2049, 18, 259, 24, 101, 0, 47, 14, 4097, 0, 59, 68, 8193, 514, 71, 0, 37, 40
Offset: 1

Views

Author

Antti Karttunen, Feb 27 2018

Keywords

Crossrefs

Programs

  • Mathematica
    With[{s = Array[Total@ MapIndexed[#1 2^(First@ #2 - 1) &, Flatten@ Map[ConstantArray[2^(PrimePi@ #1 - 1), #2] & @@ # &, FactorInteger@ #]] - Boole[# == 1]/2 &, 91]}, Table[-DivisorSum[n, MoebiusMu[n/#] s[[#]] &, # < n &], {n, Length@ s}]] (* Michael De Vlieger, Mar 13 2018 *)
  • 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))));
    A297112(n) = sumdiv(n,d,moebius(n/d)*A156552(d));
    A297168(n) = (A156552(n)-A297112(n));
    \\ Or alternatively as:
    A297168(n) = -sumdiv(n,d,(dA156552(d));
    
  • PARI
    A061395(n) = if(1==n, 0, primepi(vecmax(factor(n)[, 1])));
    A297167(n) = if(1==n, 0, (A061395(n) + (bigomega(n)-omega(n)) - 1));
    A297112(n) = if(1==n,0,2^A297167(n));
    A297168(n) = sumdiv(n,d,(dA297112(d)); \\ Antti Karttunen, Mar 13 2018
    
  • Scheme
    (define (A297168 n) (- (A156552 n) (A297112 n)))
    (define (A297168 n) (if (= 1 n) 0 (- (A156552 n) (A000079 (A297167 n)))))

Formula

a(n) = -Sum_{d|n, dA008683(n/d)*A156552(d).
a(n) = Sum_{d|n, dA297112(d).
For n > 1, a(n) = Sum_{d|n, 1A033265(A156552(d)).
a(n) = A156552(n) - A297112(n).
a(1) = 0, for n > 1, a(n) = A156552(n) - 2^A297167(n).

A324120 Binary weight of SumXOR variant of A297168: a(n) = A000120(A324180(n)).

Original entry on oeis.org

0, 0, 0, 1, 0, 2, 0, 2, 1, 2, 0, 2, 0, 2, 2, 3, 0, 2, 0, 2, 2, 2, 0, 2, 1, 2, 2, 2, 0, 2, 0, 4, 2, 2, 2, 3, 0, 2, 2, 4, 0, 2, 0, 2, 2, 2, 0, 2, 1, 2, 2, 2, 0, 2, 2, 4, 2, 2, 0, 4, 0, 2, 2, 5, 2, 2, 0, 2, 2, 2, 0, 2, 0, 2, 2, 2, 2, 2, 0, 4, 3, 2, 0, 4, 2, 2, 2, 4, 0, 2, 2, 2, 2, 2, 2, 2, 0, 2, 2, 3, 0, 2, 0, 4, 2
Offset: 1

Views

Author

Antti Karttunen, Feb 19 2019

Keywords

Crossrefs

Programs

Formula

a(n) = A000120(A324180(n)).
a(n) <= A324190(n).
a(p^k) = k-1 for all primes p and exponents k >= 1.

A364557 Möbius transform of A005941.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Jul 28 2023

Keywords

Crossrefs

Programs

  • PARI
    A364557(n) = if(1==n, 1, 2^(primepi(vecmax(factor(n)[, 1]))+(bigomega(n)-omega(n))-1));
    
  • PARI
    A005941(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]); (1+res) }; \\ (After David A. Corneth's program for A156552)
    A364557(n) = sumdiv(n,d,moebius(n/d)*A005941(d));
    
  • Python
    from sympy import factorint, primepi
    def A364557(n): return 1<1 else 1 # Chai Wah Wu, Jul 29 2023

Formula

a(n) = Sum_{d|n} A008683(n/d) * A005941(d).
a(1) = 1; for n > 1, a(n) = A297112(n) = 2^(A297113(n)-1) = 2^A297167(n).

A324181 Lexicographically earliest sequence such that a(i) = a(j) => f(i) = f(j), where f(n) = A324180(n) for n > 1 and f(1) = -1.

Original entry on oeis.org

1, 2, 2, 3, 2, 4, 2, 4, 5, 6, 2, 4, 2, 7, 8, 9, 2, 6, 2, 4, 10, 11, 2, 4, 12, 13, 8, 4, 2, 6, 2, 14, 15, 16, 17, 9, 2, 18, 19, 14, 2, 7, 2, 4, 8, 20, 2, 4, 21, 7, 22, 4, 2, 7, 23, 24, 25, 26, 2, 14, 2, 27, 8, 28, 29, 11, 2, 4, 30, 7, 2, 4, 2, 31, 10, 4, 32, 13, 2, 24, 33, 34, 2, 24, 35, 36, 37, 38, 2, 7, 39, 4, 40, 41, 42, 4, 2, 11, 8, 43, 2, 16, 2, 44, 10
Offset: 1

Views

Author

Antti Karttunen, Feb 19 2019

Keywords

Comments

For all i, j: a(i) = a(j) => A324120(i) = A324120(j).

Crossrefs

Cf. A000040 (positions of 2's), A156552, A297112, A324120, A324180.
Cf. also A300827, A323914, A324203.

Programs

  • PARI
    up_to = 65537;
    rgs_transform(invec) = { my(om = Map(), outvec = vector(length(invec)), u=1); for(i=1, length(invec), if(mapisdefined(om,invec[i]), my(pp = mapget(om, invec[i])); outvec[i] = outvec[pp] , mapput(om,invec[i],i); outvec[i] = u; u++ )); outvec; };
    A061395(n) = if(1==n, 0, primepi(vecmax(factor(n)[, 1])));
    A297167(n) = if(1==n, 0, (A061395(n) + (bigomega(n)-omega(n)) - 1));
    A297112(n) = if(1==n, 0, 2^A297167(n));
    A324180(n) = { my(v=0); fordiv(n, d, if(dA297112(d)))); (v); };
    Aux324181(n) = if((1==n),-n,A324180(n));
    v324181 = rgs_transform(vector(up_to, n, Aux324181(n)));
    A324181(n) = v324181[n];

A324203 Lexicographically earliest sequence such that a(i) = a(j) => A324202(i) = A324202(j) for all i, j >= 1.

Original entry on oeis.org

1, 2, 2, 3, 2, 4, 2, 5, 3, 4, 2, 6, 2, 4, 4, 7, 2, 8, 2, 9, 4, 4, 2, 10, 3, 4, 5, 9, 2, 11, 2, 12, 4, 4, 4, 13, 2, 4, 4, 14, 2, 11, 2, 9, 6, 4, 2, 15, 3, 8, 4, 9, 2, 16, 4, 17, 4, 4, 2, 18, 2, 4, 9, 19, 4, 11, 2, 9, 4, 11, 2, 20, 2, 4, 8, 9, 4, 11, 2, 21, 7, 4, 2, 20, 4, 4, 4, 17, 2, 22, 4, 9, 4, 4, 4, 23, 2, 8, 9, 24, 2, 11, 2, 17, 11
Offset: 1

Views

Author

Antti Karttunen, Feb 19 2019

Keywords

Comments

Restricted growth sequence transform of A324202.
For all i, j:
a(i) = a(j) => A324190(i) = A324190(j),
a(i) = a(j) => A324191(i) = A324191(j).

Crossrefs

Programs

  • PARI
    up_to = 65537;
    rgs_transform(invec) = { my(om = Map(), outvec = vector(length(invec)), u=1); for(i=1, length(invec), if(mapisdefined(om,invec[i]), my(pp = mapget(om, invec[i])); outvec[i] = outvec[pp] , mapput(om,invec[i],i); outvec[i] = u; u++ )); outvec; };
    A046523(n) = { my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]); };  \\ From A046523
    A061395(n) = if(1==n, 0, primepi(vecmax(factor(n)[, 1])));
    A297167(n) = if(1==n, 0, (A061395(n) + (bigomega(n)-omega(n)) - 1));
    A324202(n) = A046523(factorback(apply(x -> prime(1+x),apply(A297167, select(d -> d>1,divisors(n))))));
    v324203 = rgs_transform(vector(up_to, n, A324202(n)));
    A324203(n) = v324203[n];

A318891 Filter sequence combining the prime signature of n (A046523) with the largest prime factor of n (A006530).

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 10, 15, 16, 12, 17, 18, 14, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 19, 30, 14, 31, 32, 33, 23, 34, 35, 36, 37, 38, 18, 39, 40, 41, 42, 18, 30, 43, 44, 21, 19, 45, 33, 46, 47, 48, 49, 50, 25, 51, 23, 52, 53, 54, 39, 36, 55, 56, 57, 58, 18, 59, 19, 60, 61, 62, 63, 64, 65, 66, 30, 67, 46, 68, 69, 48, 23, 70, 50
Offset: 1

Views

Author

Antti Karttunen, Sep 16 2018

Keywords

Comments

Restricted growth sequence transform of A286356.
For all i, j: a(i) = a(j) => A297112(i) = A297112(j). (Also, equivalently, A297113 or A297167 in place of A297112.)

Crossrefs

Programs

  • PARI
    up_to = 65537;
    rgs_transform(invec) = { my(om = Map(), outvec = vector(length(invec)), u=1); for(i=1, length(invec), if(mapisdefined(om,invec[i]), my(pp = mapget(om, invec[i])); outvec[i] = outvec[pp] , mapput(om,invec[i],i); outvec[i] = u; u++ )); outvec; };
    A046523(n) = { my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]); }; \\ From A046523
    A061395(n) = if(1==n, 0, primepi(vecmax(factor(n)[, 1])));
    A318891aux(n) = [A046523(n), A061395(n)];
    v318891 = rgs_transform(vector(up_to,n,A318891aux(n)));
    A318891(n) = v318891[n];

A324180 SumXOR variant of A297168.

Original entry on oeis.org

0, 0, 0, 1, 0, 3, 0, 3, 2, 5, 0, 3, 0, 9, 6, 7, 0, 5, 0, 3, 10, 17, 0, 3, 4, 33, 6, 3, 0, 5, 0, 15, 18, 65, 12, 7, 0, 129, 34, 15, 0, 9, 0, 3, 6, 257, 0, 3, 8, 9, 66, 3, 0, 9, 20, 23, 130, 513, 0, 15, 0, 1025, 6, 31, 36, 17, 0, 3, 258, 9, 0, 3, 0, 2049, 10, 3, 24, 33, 0, 23, 14, 4097, 0, 23, 68, 8193, 514, 39, 0, 9, 40, 3
Offset: 1

Views

Author

Antti Karttunen, Feb 19 2019

Keywords

Crossrefs

Cf. A061395, A156552, A297106, A297112, A297167, A297168, A324181 (rgs-transform), A324120 (number of 1-bits).

Programs

  • PARI
    A061395(n) = if(1==n, 0, primepi(vecmax(factor(n)[, 1])));
    A297167(n) = if(1==n, 0, (A061395(n) + (bigomega(n)-omega(n)) - 1));
    A297112(n) = if(1==n, 0, 2^A297167(n));
    A324180(n) = { my(v=0); fordiv(n, d, if(dA297112(d)))); (v); };

Formula

a(n) = Cumulative XOR of A297112(d), where d ranges over the proper divisors d of n.

A324196 Lexicographically earliest sequence such that a(i) = a(j) => A324195(i) = A324195(j) for all i, j >= 1.

Original entry on oeis.org

1, 2, 3, 4, 5, 4, 6, 7, 8, 9, 10, 7, 11, 12, 8, 13, 14, 7, 15, 13, 16, 17, 18, 13, 19, 20, 21, 22, 23, 7, 24, 25, 26, 27, 19, 13, 28, 29, 30, 25, 31, 32, 33, 34, 21, 35, 36, 25, 37, 38, 39, 40, 41, 13, 42, 43, 44, 45, 46, 13, 47, 48, 49, 43, 50, 51, 52, 53, 54, 38, 55, 25, 56, 57, 21, 58, 37, 59, 60, 43, 49, 61, 62, 25, 63, 64, 65, 66, 67, 13, 68, 69, 70, 71, 72, 43
Offset: 1

Views

Author

Antti Karttunen, Feb 20 2019

Keywords

Comments

Restricted growth sequence transform of A324195.
For all i, j: a(i) = a(j) => A324197(i) = A324197(j) => A324190(i) = A324190(j).

Crossrefs

Programs

  • PARI
    up_to = 65537;
    rgs_transform(invec) = { my(om = Map(), outvec = vector(length(invec)), u=1); for(i=1, length(invec), if(mapisdefined(om,invec[i]), my(pp = mapget(om, invec[i])); outvec[i] = outvec[pp] , mapput(om,invec[i],i); outvec[i] = u; u++ )); outvec; };
    A061395(n) = if(1==n, 0, primepi(vecmax(factor(n)[, 1])));
    A297167(n) = if(1==n, 0, (A061395(n) + (bigomega(n)-omega(n)) - 1));
    A297112(n) = if(1==n, 0, 2^A297167(n));
    A324195(n) = { my(v=0); fordiv(n, d, v = bitor(v,A297112(d))); (v); };
    v324196 = rgs_transform(vector(up_to, n, A324195(n)));
    A324196(n) = v324196[n];

A324197 Lexicographically earliest sequence such that a(i) = a(j) => f(i) = f(j), where f(n) = A324195(n) for all other numbers except f(2) = -1 and f(n) = -2 when n is an odd prime.

Original entry on oeis.org

1, 2, 3, 4, 3, 4, 3, 5, 6, 7, 3, 5, 3, 8, 6, 9, 3, 5, 3, 9, 10, 11, 3, 9, 12, 13, 14, 15, 3, 5, 3, 16, 17, 18, 12, 9, 3, 19, 20, 16, 3, 21, 3, 22, 14, 23, 3, 16, 24, 25, 26, 27, 3, 9, 28, 29, 30, 31, 3, 9, 3, 32, 33, 29, 34, 35, 3, 36, 37, 25, 3, 16, 3, 38, 14, 39, 24, 40, 3, 29, 33, 41, 3, 16, 42, 43, 44, 45, 3, 9, 46, 47, 48, 49, 50, 29, 3, 51, 52, 16, 3, 53, 3, 54, 14
Offset: 1

Views

Author

Antti Karttunen, Feb 20 2019

Keywords

Comments

For all i, j: a(i) = a(j) => A324190(i) = A324190(j).

Crossrefs

Programs

  • PARI
    up_to = 65537;
    rgs_transform(invec) = { my(om = Map(), outvec = vector(length(invec)), u=1); for(i=1, length(invec), if(mapisdefined(om,invec[i]), my(pp = mapget(om, invec[i])); outvec[i] = outvec[pp] , mapput(om,invec[i],i); outvec[i] = u; u++ )); outvec; };
    A061395(n) = if(1==n, 0, primepi(vecmax(factor(n)[, 1])));
    A297167(n) = if(1==n, 0, (A061395(n) + (bigomega(n)-omega(n)) - 1));
    A297112(n) = if(1==n, 0, 2^A297167(n));
    A324195(n) = { my(v=0); fordiv(n, d, v = bitor(v,A297112(d))); (v); };
    Aux324197(n) = if(isprime(n),-(n%2)-1,A324195(n));
    v324197 = rgs_transform(vector(up_to, n, Aux324197(n)));
    A324197(n) = v324197[n];

A329372 Dirichlet convolution of the identity function with A156552.

Original entry on oeis.org

0, 1, 2, 5, 4, 12, 8, 17, 12, 22, 16, 44, 32, 40, 32, 49, 64, 61, 128, 78, 56, 76, 256, 132, 32, 142, 50, 136, 512, 152, 1024, 129, 104, 274, 88, 209, 2048, 532, 188, 230, 4096, 256, 8192, 252, 148, 1048, 16384, 356, 80, 159, 356, 454, 32768, 240, 160, 392, 680, 2078, 65536, 504, 131072, 4128, 248, 321, 280, 464, 262144, 858, 1328, 400
Offset: 1

Views

Author

Antti Karttunen, Nov 12 2019

Keywords

Comments

Equally, Dirichlet convolution of sigma (A000203) with A297112 (Möbius transform of A156552).

Crossrefs

Programs

  • PARI
    A156552(n) = {my(f = factor(n), 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
    A329372(n) = sumdiv(n,d,(n/d)*A156552(d));
    
  • PARI
    A061395(n) = if(1==n, 0, primepi(vecmax(factor(n)[, 1])));
    A297167(n) = if(1==n, 0, (A061395(n) + (bigomega(n)-omega(n)) - 1));
    A297112(n) = if(1==n,0,2^A297167(n));
    A329372(n) = sumdiv(n,d,sigma(n/d)*A297112(d));

Formula

a(n) = Sum_{d|n} d * A156552(n/d).
a(n) = Sum_{d|n} A000203(n/d) * A297112(d).
A000265(a(n)) = A329374(n).
Previous Showing 11-20 of 25 results. Next