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.

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

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Author

Antti Karttunen, Oct 05 2023

Keywords

Crossrefs

Programs

A366261 The least number with the same prime signature as A366260, where A366260 is Doudna sequence permuted by May code.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Oct 05 2023

Keywords

Crossrefs

Cf. A005940, A046523, A303767, A366260, A366262 (rgs-transform).
Cf. also A278219, A278222.

Programs

Formula

a(n) = A046523(A366260(n)).
a(n) = A278222(A303767(n)).
A001222(a(n)) = A366254(n).

A366280 Lexicographically earliest infinite sequence such that a(i) = a(j) => A366279(i) = A366279(j) for all i, j >= 0.

Original entry on oeis.org

1, 2, 3, 2, 4, 3, 5, 2, 6, 4, 7, 5, 7, 3, 5, 2, 8, 6, 9, 7, 10, 7, 11, 5, 9, 4, 7, 5, 7, 3, 5, 2, 12, 8, 13, 9, 14, 10, 15, 7, 14, 9, 15, 11, 15, 7, 11, 5, 13, 6, 9, 7, 10, 7, 11, 5, 9, 4, 7, 5, 7, 3, 5, 2, 16, 12, 17, 13, 18, 14, 19, 9, 20, 14, 21, 15, 21, 10, 15, 7, 18, 13, 19, 15, 21, 15, 22, 11, 19, 9, 15, 11, 15
Offset: 0

Views

Author

Antti Karttunen, Oct 06 2023

Keywords

Comments

Restricted growth sequence transform of A366279.
For all i, j >= 0, a(i) = a(j) => A290251(i) = A290251(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; };
    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));
    v366280 = rgs_transform(vector(1+up_to,n,A366279(n-1)));
    A366280(n) = v366280[1+n];
Showing 1-3 of 3 results.