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 1-8 of 8 results.

A349399 a(n) = A349397(n) + A349398(n).

Original entry on oeis.org

2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, -10, 0, 0, 0, 0, 0, 16, 25, 0, 0, 0, 0, 0, 0, -80, 0, 0, 0, -12, 0, 0, 0, 64, 0, -6, 0, 0, 0, 60, 0, 4, 0, 0, 0, 0, 30, 0, 0, -96, 0, 0, 0, 18, 0, 0, 0, -48, 0, -10, 0, 0, 0, 0, 0, 24, 0, -190
Offset: 1

Views

Author

Antti Karttunen, Nov 19 2021

Keywords

Crossrefs

Programs

Formula

a(1) = 2, and for n > 1, a(n) = -Sum_{d|n, 1A349397(d) * A349398(n/d). [As the sequences are Dirichlet inverses of each other]

A349614 Dirichlet convolution of A064664 (the inverse permutation of EKG-permutation, A064413) with the Dirichlet inverse of A064413.

Original entry on oeis.org

1, 0, 1, -3, 7, -7, 2, 6, -8, -10, 5, 9, 14, 2, -41, -1, 17, 27, 15, -6, -38, -18, 13, 10, -32, -29, 18, 33, 18, 62, 29, -13, -31, -53, -107, 25, 48, -51, -86, 13, 30, 116, 58, 23, 88, -34, 37, -47, -30, 56, -113, 3, 45, -39, -137, -154, -73, -67, 41, 160, 84, -91, 174, 56, -154, 152, 91, 6, -113, 246, 58, -185, 56
Offset: 1

Views

Author

Antti Karttunen, Nov 23 2021

Keywords

Comments

Obviously, convolving this with A064413 gives its inverse permutation A064664.

Crossrefs

Cf. A064413, A064664, A349400, A349613 (Dirichlet inverse), A349615 (sum with it), A349617.
Cf. also pairs A349376, A349377 and A349397, A349398 for similar constructions.

Programs

  • PARI
    up_to = 32768;
    v064413 = readvec("b064413_upto65539_terms_only.txt"); \\ Data prepared with Chai Wah Wu's Dec 08 2014 Python-program given in A064413.
    A064413(n) = v064413[n];
    \\ Then its inverse A064664 is prepared:
    m064664 = Map();
    for(n=1,65539,mapput(m064664,A064413(n),n));
    A064664(n) = mapget(m064664,n);
    memoA349400 = Map();
    A349400(n) = if(1==n,1,my(v); if(mapisdefined(memoA349400,n,&v), v, v = -sumdiv(n,d,if(dA064413(n/d)*A349400(d),0)); mapput(memoA349400,n,v); (v)));
    A349614(n) = sumdiv(n,d,A064664(d)*A349400(n/d));

Formula

a(n) = Sum_{d|n} A064664(d) * A349400(n/d).

A349376 Dirichlet convolution of A006368 with the Dirichlet inverse of A006369, where A006368 is the "amusical permutation", and A006369 is its inverse permutation.

Original entry on oeis.org

1, 0, 0, 1, -3, 5, -4, -2, 1, 11, -7, -7, -7, 14, 7, 4, -10, 2, -11, -22, 10, 25, -14, 16, 7, 25, 0, -26, -17, -41, -18, -8, 17, 36, 34, 7, -21, 39, 17, 52, -24, -52, -25, -48, 1, 50, -28, -36, 8, -51, 24, -48, -31, 7, 62, 60, 27, 61, -35, 136, -35, 64, 0, 16, 62, -93, -39, -70, 34, -178, -42, -26, -42, 75, -27, -74
Offset: 1

Views

Author

Antti Karttunen, Nov 17 2021

Keywords

Comments

Obviously, convolving this sequence with A006369 gives its inverse A006368 from n >= 1 onward.

Crossrefs

Cf. A006368, A006369, A349368, A349377 (Dirichlet inverse), A349378 (sum with it).
Cf. also pairs A349613, A349614 and A349397, A349398 for similar constructions.

Programs

Formula

a(n) = Sum_{d|n} A006368(d) * A349368(n/d).

A349377 Dirichlet convolution of A006369 with the Dirichlet inverse of A006368, where A006368 is the "amusical permutation", and A006369 is its inverse permutation.

Original entry on oeis.org

1, 0, 0, -1, 3, -5, 4, 2, -1, -11, 7, 7, 7, -14, -7, -3, 10, -2, 11, 16, -10, -25, 14, -6, 2, -25, 0, 18, 17, 11, 18, 4, -17, -36, -10, 20, 21, -39, -17, -18, 24, 12, 25, 34, -7, -50, 28, 2, 8, -15, -24, 34, 31, 3, -20, -16, -27, -61, 35, 30, 35, -64, -8, -5, -20, 23, 39, 50, -34, 6, 42, -44, 42, -75, -15, 52, -22, 23
Offset: 1

Views

Author

Antti Karttunen, Nov 17 2021

Keywords

Comments

Obviously, convolving this sequence with A006368 gives its inverse A006369 from n >= 1 onward.

Crossrefs

Cf. A006368, A006369, A349351, A349376 (Dirichlet inverse), A349378 (sum with it).
Cf. also pairs A349613, A349614 and A349397, A349398 for similar constructions.

Programs

Formula

a(n) = Sum_{d|n} A006369(d) * A349351(n/d).
a(n) = A349378(n) - A349376(n).

A349397 Dirichlet convolution of A064216 with the Dirichlet inverse of its inverse permutation.

Original entry on oeis.org

1, 0, 0, 0, 0, -1, 5, -8, 0, 6, 3, -2, 0, -19, 5, 4, 4, -20, 19, -22, -6, 15, -3, 8, 0, 0, -16, -16, 18, -24, 40, -70, -9, 24, -21, 8, 50, -55, -8, 24, -6, 31, 15, -58, -20, 17, 31, -92, -2, -70, 37, 24, 0, 20, 49, 18, -6, -26, 13, -33, 15, -62, -158, -20, 22, -15, 49, -130, 67, 48, 49, -58, 29, -112, -4, 60, -73, -16
Offset: 1

Views

Author

Antti Karttunen, Nov 19 2021

Keywords

Comments

Dirichlet convolution of A064216 with A323893, which is the Dirichlet inverse of A048673. Therefore, convolving A048673 with this sequence gives A064216.
Note how for n = 1 .. 35, a(n) = -A349398(n).

Crossrefs

Cf. A003961, A048673, A064216, A064989, A323893, A349398 (Dirichlet inverse), A349399 (sum with it), A349384.
Cf. also pairs A349376, A349377 and A349613, A349614 for similar constructions.

Programs

  • PARI
    A048673(n) = { my(f = factor(n)); for (i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); (1/2)*(1+factorback(f)); };
    A064216(n) = { my(f = factor(n+n-1)); 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); };
    memoA323893 = Map();
    A323893(n) = if(1==n,1,my(v); if(mapisdefined(memoA323893,n,&v), v, v = -sumdiv(n,d,if(dA048673(n/d)*A323893(d),0)); mapput(memoA323893,n,v); (v)));
    A349397(n) = sumdiv(n,d,A064216(n/d)*A323893(d));

Formula

a(n) = Sum_{d|n} A064216(n/d) * A323893(d).

A349613 Dirichlet convolution of A064413 (EKG-permutation) with the Dirichlet inverse of its inverse permutation.

Original entry on oeis.org

1, 0, -1, 3, -7, 7, -2, -6, 9, 10, -5, -15, -14, -2, 55, 10, -17, -41, -15, -36, 42, 18, -13, 44, 81, 29, -35, -45, -18, -180, -29, -23, 41, 53, 135, 99, -48, 51, 114, 131, -30, -140, -58, -53, -303, 34, -37, -120, 34, -196, 147, -87, -45, 226, 207, 166, 103, 67, -41, 466, -84, 91, -288, 13, 350, -258, -91, -108
Offset: 1

Views

Author

Antti Karttunen, Nov 23 2021

Keywords

Comments

Obviously, convolving this with A064664 gives A064413 back.

Crossrefs

Cf. A064413, A064664, A323411, A349614 (Dirichlet inverse), A349615 (sum with it), A349616.
Cf. also pairs A349376, A349377 and A349397, A349398 for similar constructions.

Programs

  • PARI
    up_to = 32768;
    v064413 = readvec("b064413_upto65539_terms_only.txt"); \\ Data prepared with Chai Wah Wu's Dec 08 2014 Python-program given in A064413.
    A064413(n) = v064413[n];
    \\ Then its inverse A064664 is prepared:
    m064664 = Map();
    for(n=1,65539,mapput(m064664,A064413(n),n));
    A064664(n) = mapget(m064664,n);
    DirInverseCorrect(v) = { my(u=vector(#v)); u[1] = (1/v[1]); for(n=2, #v, u[n] = (-u[1]*sumdiv(n, d, if(dA064664(n)));
    A323411(n) = v323411[n];
    A349613(n) = sumdiv(n,d,A064413(d)*A323411(n/d));

Formula

a(n) = Sum_{d|n} A064413(d) * A323411(n/d).

A349358 Dirichlet inverse of A064216, which is A064989(2n-1), where A064989 is fully multiplicative with a(2) = 1 and a(p) = prevprime(p) for odd primes p.

Original entry on oeis.org

1, -2, -3, -1, -4, 5, -11, 6, -4, -1, -10, 3, -9, 36, 1, -24, -14, 25, -31, 38, 29, -1, -12, -29, -9, 10, 4, -11, -34, 53, -59, 62, 27, -5, 50, -41, -71, 106, 19, -83, -16, -125, -39, 98, 51, -7, -58, 184, 32, 112, -13, -15, -30, -84, -27, -170, 77, 79, -44, -109, -49, 162, 184, -84, -10, 31, -85, 192, -59, -75, -86
Offset: 1

Views

Author

Antti Karttunen, Nov 17 2021

Keywords

Crossrefs

Programs

  • PARI
    A064989(n) = { my(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); };
    A064216(n) = A064989((2*n)-1);
    memoA349358 = Map();
    A349358(n) = if(1==n,1,my(v); if(mapisdefined(memoA349358,n,&v), v, v = -sumdiv(n,d,if(dA064216(n/d)*A349358(d),0)); mapput(memoA349358,n,v); (v)));

Formula

a(1) = 1; a(n) = -Sum_{d|n, d < n} A064216(n/d) * a(d).
a(n) = A349359(n) - A064216(n).

A349571 Dirichlet convolution of A048673 with A055615 (Dirichlet inverse of n).

Original entry on oeis.org

1, 0, 0, 1, -1, 2, -1, 4, 4, 3, -4, 4, -4, 5, 6, 13, -7, 6, -7, 5, 10, 6, -8, 10, 5, 8, 24, 9, -13, -2, -12, 40, 12, 9, 16, 16, -16, 11, 16, 11, -19, -2, -19, 8, 14, 14, -20, 28, 19, 9, 18, 12, -23, 26, 22, 21, 22, 15, -28, 2, -27, 18, 26, 121, 28, -8, -31, 11, 28, -8, -34, 46, -33, 20, 18, 15, 34, -8, -37, 29, 124
Offset: 1

Views

Author

Antti Karttunen, Nov 23 2021

Keywords

Comments

Also Dirichlet convolution of A349385 with A349387.

Crossrefs

Cf. A048673, A055615, A349385, A349387, A349572 (Dirichlet inverse).
Cf. also A349398, A349573.

Programs

  • Mathematica
    f[p_, e_] := NextPrime[p]^e; s[1] = 1; s[n_] := (1 + Times @@ f @@@ FactorInteger[n])/2; a[n_] := DivisorSum[n, # * MoebiusMu[#] * s[n/#] &]; Array[a, 100] (* Amiram Eldar, Nov 23 2021 *)
  • PARI
    A048673(n) = { my(f = factor(n)); for (i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); (1/2)*(1+factorback(f)); };
    A055615(n) = (n*moebius(n));
    A349571(n) = sumdiv(n,d,A048673(n/d)*A055615(d));

Formula

a(n) = Sum_{d|n} A048673(n/d) * A055615(d).
a(n) = Sum_{d|n} A349385(n/d) * A349387(d).
Showing 1-8 of 8 results.