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.

A064744 A064413(n) written in base of primes, read from right to left, written as n-th row of a table.

Original entry on oeis.org

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

Views

Author

N. J. A. Sloane, Oct 19 2001

Keywords

Examples

			Triangle begins:
  0;
  1;
  2;
  1,1;
  1,0;
  2,0;
  1,2;
  3;
  ...
		

Crossrefs

A064741(n) gives length of n-th row. See A064743 for another version. See A064301 for rightmost column.

A304735 a(n) = A048675(A064413(n)).

Original entry on oeis.org

0, 1, 2, 3, 2, 4, 4, 3, 5, 4, 6, 5, 9, 8, 10, 5, 4, 6, 17, 16, 18, 6, 7, 8, 12, 10, 33, 32, 34, 6, 5, 65, 64, 66, 11, 129, 128, 130, 8, 7, 18, 257, 256, 258, 6, 9, 34, 7, 11, 16, 12, 8, 20, 36, 13, 513, 512, 514, 19, 1025, 1024, 1026, 7, 6, 66, 2049, 2048, 2050, 10, 35, 130, 8, 4097, 4096, 4098, 8, 12, 24, 19, 8193, 8192, 8194, 9, 68, 132, 10
Offset: 1

Views

Author

Antti Karttunen, May 18 2018

Keywords

Crossrefs

Programs

Formula

a(n) = A048675(A064413(n)).

A304737 Restricted growth sequence transform of A278222(A064413(n)).

Original entry on oeis.org

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

Views

Author

Antti Karttunen, May 18 2018

Keywords

Comments

Sequence allots a distinct value for each distinct multiset formed from the lengths of 1-runs in the binary representation of A064413(n), the n-th term of EKG-sequence. Compare to the scatter plot of A286622.

Crossrefs

Programs

  • PARI
    \\ 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; };
    A005940(n) = { my(p=2, t=1); n--; until(!n\=2, if((n%2), (t*=p), p=nextprime(p+1))); t };
    A046523(n) = { my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]); };  \\ From A046523
    A278222(n) = A046523(A005940(1+n));
    v304737 = rgs_transform(vector(65539,n,A278222(A064413(n))));
    A304737(n) = v304737[n];

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];
Showing 1-4 of 4 results.