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.

A366262 Lexicographically earliest infinite sequence such that a(i) = a(j) => A366261(i) = A366261(j) for all i, j >= 0.

Original entry on oeis.org

1, 2, 3, 2, 3, 2, 4, 5, 6, 2, 4, 7, 4, 5, 3, 7, 8, 2, 4, 7, 4, 7, 4, 9, 8, 10, 3, 7, 11, 7, 6, 5, 6, 2, 4, 7, 4, 7, 4, 9, 8, 12, 4, 9, 13, 9, 8, 7, 13, 12, 3, 7, 11, 7, 11, 7, 13, 14, 15, 5, 8, 14, 8, 10, 15, 2, 4, 7, 4, 7, 4, 9, 8, 12, 4, 9, 13, 9, 8, 7, 13, 16, 4, 9, 13, 9, 13, 9, 17, 16, 18, 7, 13, 19, 13, 12, 8, 10
Offset: 0

Views

Author

Antti Karttunen, Oct 05 2023

Keywords

Comments

Restricted growth sequence transform of A366261.
For all i, j >= 0: a(i) = a(j) => A366254(i) = A366254(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; };
    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]); };
    A209229(n) = (n && !bitand(n,n-1));
    A053644(n) = { my(k=1); while(k<=n, k<<=1); (k>>1); };
    A303767(n) = if(!n,n,if(A209229(n),n+A303767(n-1),A053644(n)+A303767(n-A053644(n)-1)));
    A366260(n) = A005940(1+A303767(n));
    A366261(n) = A046523(A366260(n));
    v366262 = rgs_transform(vector(1+up_to,n,A366261(n-1)));
    A366262(n) = v366262[1+n];

A366260 Doudna sequence permuted by May code: a(n) = A005940(1+A303767(n)).

Original entry on oeis.org

1, 2, 4, 3, 9, 5, 6, 8, 16, 7, 10, 12, 15, 27, 25, 18, 54, 11, 14, 20, 21, 45, 35, 30, 24, 32, 49, 50, 36, 75, 81, 125, 625, 13, 22, 28, 33, 63, 55, 42, 40, 48, 77, 70, 60, 105, 135, 175, 90, 162, 121, 98, 100, 147, 225, 245, 150, 72, 64, 343, 250, 108, 375, 243, 729, 17, 26, 44, 39, 99, 65, 66, 56, 80, 91, 110
Offset: 0

Views

Author

Antti Karttunen, Oct 05 2023

Keywords

Crossrefs

Programs

A366254 Binary weight of May code (A303767).

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Oct 05 2023

Keywords

Crossrefs

Programs

Formula

a(n) = A000120(A303767(n)).
a(n) = A001221(A303760(n)) = A001222(A303760(n)) = A001222(A366261(n)).
a(n) = A064547(A303771(n)).

A366279 The least number with same prime signature as A366275, where A366275(n) = A163511(A057889(n)).

Original entry on oeis.org

1, 2, 4, 2, 8, 4, 6, 2, 16, 8, 12, 6, 12, 4, 6, 2, 32, 16, 24, 12, 36, 12, 30, 6, 24, 8, 12, 6, 12, 4, 6, 2, 64, 32, 48, 24, 72, 36, 60, 12, 72, 24, 60, 30, 60, 12, 30, 6, 48, 16, 24, 12, 36, 12, 30, 6, 24, 8, 12, 6, 12, 4, 6, 2, 128, 64, 96, 48, 144, 72, 120, 24, 216, 72, 180, 60, 180, 36, 60, 12, 144, 48, 120, 60
Offset: 0

Views

Author

Antti Karttunen, Oct 06 2023

Keywords

Crossrefs

Cf. A046523, A057889, A163511, A278531, A366275, A366280 (rgs-transform).
Cf. also A286601, A366261.

Programs

  • PARI
    A046523(n) = { my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]); };
    A030101(n) = if(n<1,0,subst(Polrev(binary(n)),x,2));
    A057889(n) = if(!n,n,A030101(n/(2^valuation(n,2))) * (2^valuation(n, 2)));
    A163511(n) = if(!n, 1, my(p=2, t=1); while(n>1, if(!(n%2), (t*=p), p=nextprime(1+p)); n >>= 1); (t*p));
    A366275(n) = A163511(A057889(n));
    A366279(n) = A046523(A366275(n));

Formula

a(n) = A278531(A057889(n)).
Showing 1-4 of 4 results.