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 1-2 of 2 results.

A322591 Lexicographically earliest such sequence a that for all i, j, a(i) = a(j) => f(i) = f(j), where f(n) = 0 for odd primes, and A007947(n) for any other number.

Original entry on oeis.org

1, 2, 3, 2, 3, 4, 3, 2, 5, 6, 3, 4, 3, 7, 8, 2, 3, 4, 3, 6, 9, 10, 3, 4, 11, 12, 5, 7, 3, 13, 3, 2, 14, 15, 16, 4, 3, 17, 18, 6, 3, 19, 3, 10, 8, 20, 3, 4, 21, 6, 22, 12, 3, 4, 23, 7, 24, 25, 3, 13, 3, 26, 9, 2, 27, 28, 3, 15, 29, 30, 3, 4, 3, 31, 8, 17, 32, 33, 3, 6, 5, 34, 3, 19, 35, 36, 37, 10, 3, 13, 38, 20, 39, 40, 41, 4, 3, 7, 14, 6, 3, 42, 3, 12, 43
Offset: 1

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Author

Antti Karttunen, Dec 18 2018

Keywords

Comments

For all i, j:
a(i) = a(j) => A066086(i) = A066086(j),
a(i) = a(j) => A322354(i) = A322354(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; };
    A007947(n) = factorback(factorint(n)[, 1]);
    Aux322591(n) = if((n>2)&&isprime(n),0,A007947(n));
    v322591 = rgs_transform(vector(up_to, n, Aux322591(n)));
    A322591(n) = v322591[n];

A336147 Lexicographically earliest infinite sequence such that a(i) = a(j) => A020639(i) = A020639(j) and A278221(i) = A278221(j), for all i, j >= 1.

Original entry on oeis.org

1, 2, 3, 2, 4, 5, 6, 2, 3, 7, 8, 5, 9, 10, 11, 2, 12, 5, 13, 7, 14, 15, 16, 5, 4, 17, 3, 10, 18, 19, 20, 2, 21, 22, 23, 5, 24, 25, 26, 7, 27, 28, 29, 15, 11, 30, 31, 5, 6, 7, 32, 17, 33, 5, 34, 10, 35, 36, 37, 19, 38, 39, 14, 2, 40, 41, 42, 22, 43, 28, 44, 5, 45, 46, 11, 25, 47, 48, 49, 7, 3, 50, 51, 28, 52, 53, 54, 15, 55, 19, 56, 30, 57, 58, 59, 5, 60, 10, 21, 7, 61, 62, 63, 17, 64
Offset: 1

Views

Author

Antti Karttunen, Jul 12 2020

Keywords

Comments

Restricted growth sequence transform of the ordered pair [A020639(n), A278221(n)].
For all i, j:
A324400(i) = A324400(j) => A336146(i) = A336146(j) => a(i) = a(j),
a(i) = a(j) => A243055(i) = A243055(j),
a(i) = a(j) => A336150(i) = A336150(j).

Crossrefs

First differs from A322590 at a(70) = 28 instead of 44.

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; };
    A020639(n) = if(1==n, n, factor(n)[1, 1]);
    A064989(n) = {my(f); f = factor(n); if((n>1 && f[1,1]==2), f[1,2] = 0); for (i=1, #f~, f[i,1] = precprime(f[i,1]-1)); factorback(f)};
    A122111(n) = if(1==n,n,prime(bigomega(n))*A122111(A064989(n)));
    A046523(n) = { my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]); }; \\ From A046523
    A278221(n) = A046523(A122111(n));
    Aux336147(n) = [A020639(n),A278221(n)];
    v336147 = rgs_transform(vector(up_to, n, Aux336147(n)));
    A336147(n) = v336147[n];
Showing 1-2 of 2 results.