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 1-3 of 3 results.

A064301 Rightmost column of A064744; 2-adic valuation of the EKG-sequence.

Original entry on oeis.org

0, 1, 2, 1, 0, 0, 2, 3, 1, 0, 0, 1, 1, 0, 0, 3, 4, 2, 1, 0, 0, 0, 1, 0, 0, 2, 1, 0, 0, 2, 5, 1, 0, 0, 1, 1, 0, 0, 0, 3, 2, 1, 0, 0, 4, 1, 2, 1, 3, 0, 0, 2, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 3, 6, 2, 1, 0, 0, 0, 1, 2, 4, 1, 0, 0, 0, 2, 0, 3, 1, 0, 0, 1, 0, 0, 2, 2, 1, 0, 0, 5, 1, 0, 3, 1, 0, 0, 2, 1, 0, 0, 1, 1, 4, 2
Offset: 1

Views

Author

N. J. A. Sloane, Oct 20 2001

Keywords

Comments

Exponent of highest power of 2 dividing A064413(n).

Crossrefs

Programs

  • Mathematica
    IntegerExponent[#, 2] & /@ Nest[Append[#, Block[{k = 3}, While[Or[MemberQ[#, k], GCD[#[[-1]], k] == 1], k++]; k]] &, {1, 2}, 105] (* Michael De Vlieger, May 22 2018 *)
  • PARI
    A064301(n) = valuation(A064413(n),2); \\ Needs also code from A064413. - Antti Karttunen, May 18 2018

Extensions

More terms from Vladeta Jovovic, Oct 21 2001
An alternative description added to name by Antti Karttunen, May 18 2018

A304736 Restricted growth sequence transform of A048675(A064413(n)).

Original entry on oeis.org

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

Views

Author

Antti Karttunen, May 18 2018

Keywords

Crossrefs

Programs

  • PARI
    A048675(n) = { my(f = factor(n)); sum(k=1, #f~, f[k, 2]*2^primepi(f[k, 1]))/2; };
    A304735(n) = A048675(A064413(n)); \\ Needs also code for A064413.
    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; };
    v304736 = rgs_transform(vector(65539,n,A304735(n)));
    A304736(n) = v304736[n];

A304739 a(n) = A056239(A064413(n)).

Original entry on oeis.org

0, 1, 2, 3, 2, 4, 4, 3, 4, 3, 5, 5, 5, 4, 6, 5, 4, 5, 6, 5, 7, 6, 6, 6, 7, 6, 7, 6, 8, 6, 5, 8, 7, 9, 7, 9, 8, 10, 7, 6, 7, 10, 9, 11, 6, 7, 8, 7, 7, 8, 8, 7, 8, 9, 8, 11, 10, 12, 8, 12, 11, 13, 7, 6, 9, 13, 12, 14, 8, 9, 10, 7, 14, 13, 15, 8, 8, 9, 8, 15, 14, 16, 8, 10, 11, 8, 11, 16, 15, 17, 7, 9, 10, 9, 10, 9, 9, 8, 17, 16, 18, 11, 9, 8, 12
Offset: 1

Views

Author

Antti Karttunen, May 19 2018

Keywords

Comments

For visualizing of the EKG-sequence, A064413.

Crossrefs

Programs

Formula

a(n) = A056239(A064413(n)).
Showing 1-3 of 3 results.