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 31-34 of 34 results.

A283975 Odd bisection of A264977.

Original entry on oeis.org

1, 3, 1, 7, 5, 7, 1, 15, 13, 7, 5, 11, 13, 15, 1, 31, 29, 7, 13, 3, 1, 11, 5, 19, 21, 15, 13, 19, 29, 31, 1, 63, 61, 7, 29, 19, 25, 3, 13, 11, 9, 11, 1, 23, 25, 19, 5, 35, 37, 15, 21, 11, 9, 19, 13, 43, 37, 31, 29, 35, 61, 63, 1, 127, 125, 7, 61, 51, 41, 19, 29, 59, 49, 3, 25, 31, 17, 11, 13, 27, 25, 11, 9, 31, 21, 23, 1, 47, 33, 19, 25, 63, 41, 35, 5, 67, 69
Offset: 0

Views

Author

Antti Karttunen, Mar 25 2017

Keywords

Crossrefs

Programs

Formula

a(n) = A264977((2*n)+1).
a(n) = A248663(A277324(n)).
A000120(a(n)) = A284266(n).

A335424 Lexicographically earliest infinite sequence such that a(i) = a(j) => A046523(A335423(i)) = A046523(A335423(j)) for all i, j >= 1.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Jun 13 2020

Keywords

Comments

For all i, j: A305800(i) = A305800(j) => a(i) = a(j) => A162642(i) = A162642(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; };
    A048675(n) = { my(f = factor(n)); sum(k=1, #f~, f[k, 2]*2^primepi(f[k, 1]))/2; };
    A248663(n) = A048675(core(n));
    A005940(n) = { my(p=2, t=1); n--; until(!n\=2, if((n%2), (t*=p), p=nextprime(p+1))); t };
    A335423(n) = A005940(1+A248663(n));
    A046523(n) = { my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]); };
    v335424 = rgs_transform(vector(up_to,n,A046523(A335423(n))));
    A335424(n) = v335424[n];

A335425 Lexicographically earliest infinite sequence such that a(i) = a(j) => A000188(i) = A000188(j) and A335424(i) = A335424(j) for all i, j >= 1.

Original entry on oeis.org

1, 2, 2, 3, 2, 4, 2, 5, 6, 7, 2, 5, 2, 7, 4, 8, 2, 9, 2, 5, 7, 7, 2, 10, 11, 7, 9, 5, 2, 12, 2, 13, 7, 7, 4, 14, 2, 7, 7, 15, 2, 16, 2, 5, 9, 7, 2, 13, 17, 18, 7, 5, 2, 19, 7, 15, 7, 7, 2, 10, 2, 7, 9, 20, 7, 16, 2, 5, 7, 16, 2, 21, 2, 7, 18, 5, 4, 16, 2, 13, 22, 7, 2, 15, 7, 7, 7, 15, 2, 23, 7, 5, 7, 7, 7, 24, 2, 25, 9, 26, 2, 16, 2, 15, 12
Offset: 1

Views

Author

Antti Karttunen, Jun 13 2020

Keywords

Comments

Restricted growth sequence transform of the ordered pair [A000188(n), A046523(A335423(n))].
For all i, j: A305800(i) = A305800(j) => a(i) = a(j) => A001222(i) = A001222(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; };
    A000188(n) = core(n, 1)[2]; \\ From A000188
    A048675(n) = { my(f = factor(n)); sum(k=1, #f~, f[k, 2]*2^primepi(f[k, 1]))/2; };
    A248663(n) = A048675(core(n));
    A005940(n) = { my(p=2, t=1); n--; until(!n\=2, if((n%2), (t*=p), p=nextprime(p+1))); t };
    A335423(n) = A005940(1+A248663(n));
    A046523(n) = { my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]); };  \\ From A046523
    Aux335425(n) = [A000188(n),A046523(A335423(n))];
    v335425 = rgs_transform(vector(up_to,n,Aux335425(n)));
    A335425(n) = v335425[n];

A335426 a(1) = 0; thereafter a(2^(2^k)) = 0 for k > 0, and for other even numbers n, a(n) = 1+a(n/2), and for odd numbers n, a(n) = 2*a(A064989(n)).

Original entry on oeis.org

0, 1, 2, 0, 4, 3, 8, 1, 0, 5, 16, 4, 32, 9, 6, 0, 64, 1, 128, 6, 10, 17, 256, 5, 0, 33, 2, 10, 512, 7, 1024, 1, 18, 65, 12, 2, 2048, 129, 34, 7, 4096, 11, 8192, 18, 8, 257, 16384, 6, 0, 1, 66, 34, 32768, 3, 20, 11, 130, 513, 65536, 8, 131072, 1025, 12, 2, 36, 19, 262144, 66, 258, 13, 524288, 3, 1048576, 2049, 2, 130, 24, 35, 2097152, 8, 0, 4097
Offset: 1

Views

Author

Antti Karttunen, Jun 15 2020

Keywords

Crossrefs

Cf. A082522 (gives indices of zeros after a(1)=0).

Programs

Formula

a(1) = 0, and then after, a(2^(2^k)) = 0 for k > 0, and for other even numbers n, a(n) = 1+a(n/2), and for odd numbers n, a(n) = 2*a(A064989(n)).
a(n) = A335427(A225546(n)).
a(A003961(n)) = 2 * a(n).
Previous Showing 31-34 of 34 results.