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 1-4 of 4 results.

A300251 Möbius transform of arithmetic derivative (A003415).

Original entry on oeis.org

0, 1, 1, 3, 1, 3, 1, 8, 5, 5, 1, 8, 1, 7, 6, 20, 1, 11, 1, 14, 8, 11, 1, 20, 9, 13, 21, 20, 1, 14, 1, 48, 12, 17, 10, 28, 1, 19, 14, 36, 1, 20, 1, 32, 26, 23, 1, 48, 13, 29, 18, 38, 1, 39, 14, 52, 20, 29, 1, 36, 1, 31, 36, 112, 16, 32, 1, 50, 24, 34, 1, 68, 1, 37, 38, 56, 16, 38, 1, 88, 81, 41, 1, 52, 20, 43, 30, 84, 1, 50
Offset: 1

Views

Author

Antti Karttunen, Mar 08 2018

Keywords

Crossrefs

Programs

  • PARI
    A003415(n) = {my(fac); if(n<1, 0, fac=factor(n); sum(i=1, matsize(fac)[1], n*fac[i, 2]/fac[i, 1]))}; \\ From A003415
    A300251(n) = sumdiv(n,d,moebius(n/d)*A003415(d));

Formula

a(n) = Sum_{d|n} A008683(n/d)*A003415(d).
a(n) = A003415(n) - A300252(n).

A300252 Difference between arithmetic derivative (A003415) and its Möbius transform (A300251).

Original entry on oeis.org

0, 0, 0, 1, 0, 2, 0, 4, 1, 2, 0, 8, 0, 2, 2, 12, 0, 10, 0, 10, 2, 2, 0, 24, 1, 2, 6, 12, 0, 17, 0, 32, 2, 2, 2, 32, 0, 2, 2, 32, 0, 21, 0, 16, 13, 2, 0, 64, 1, 16, 2, 18, 0, 42, 2, 40, 2, 2, 0, 56, 0, 2, 15, 80, 2, 29, 0, 22, 2, 25, 0, 88, 0, 2, 17, 24, 2, 33, 0, 88, 27, 2, 0, 72, 2, 2, 2, 56, 0, 73, 2, 28, 2, 2, 2, 160, 0, 22, 19, 62, 0, 41, 0, 64, 27
Offset: 1

Views

Author

Antti Karttunen, Mar 08 2018

Keywords

Crossrefs

Cf. A001248 (seems to give the positions of 1's), A006881 (seems to give the positions of 2's).

Programs

  • PARI
    A003415(n) = {my(fac); if(n<1, 0, fac=factor(n); sum(i=1, matsize(fac)[1], n*fac[i, 2]/fac[i, 1]))}; \\ From A003415
    A300252(n) = -sumdiv(n,d,(dA003415(d));

Formula

a(n) = A003415(n) - A300251(n).
a(n) = -Sum_{d|n, dA008683(n/d)*A003415(d).

A300245 Filter sequence combining arithmetic derivative (A003415) with its Möbius transform (A300251).

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Mar 08 2018

Keywords

Comments

Restricted growth sequence transform of ordered pair [A003415(n), A300251(n)].

Examples

			a(16) = a(28) (= 11) because both A003415(16) = A003415(28) = 32 and A300251(16) = A300251(28) = 20.
		

Crossrefs

Programs

  • PARI
    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; };
    write_to_bfile(start_offset,vec,bfilename) = { for(n=1, length(vec), write(bfilename, (n+start_offset)-1, " ", vec[n])); }
    A003415(n) = {my(fac); if(n<1, 0, fac=factor(n); sum(i=1, matsize(fac)[1], n*fac[i, 2]/fac[i, 1]))}; \\ From A003415
    A300251(n) = sumdiv(n,d,moebius(n/d)*A003415(d));
    Aux300245(n) = [A003415(n), A300251(n)];
    write_to_bfile(1,rgs_transform(vector(65537,n,Aux300245(n))),"b300245.txt");

A340070 a(n) = gcd(A003415(n), A069359(n)).

Original entry on oeis.org

0, 1, 1, 2, 1, 5, 1, 4, 3, 7, 1, 2, 1, 9, 8, 8, 1, 3, 1, 2, 10, 13, 1, 4, 5, 15, 9, 2, 1, 31, 1, 16, 14, 19, 12, 30, 1, 21, 16, 4, 1, 41, 1, 2, 3, 25, 1, 8, 7, 5, 20, 2, 1, 9, 16, 4, 22, 31, 1, 2, 1, 33, 3, 32, 18, 61, 1, 2, 26, 59, 1, 12, 1, 39, 5, 2, 18, 71, 1, 8, 27, 43, 1, 2, 22, 45, 32, 4, 1, 3, 20, 2, 34, 49, 24
Offset: 1

Views

Author

Antti Karttunen, Dec 30 2020

Keywords

Crossrefs

Programs

Formula

a(n) = gcd(A003415(n), A069359(n)) = gcd(A003415(n), A329039(n)).
For all squarefree k, a(k) = A003415(k) = A069359(k).
Showing 1-4 of 4 results.