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 1-5 of 5 results.

A373980 Lexicographically earliest infinite sequence such that a(i) = a(j) => f(i) = f(j), where f(n) = [A003415(n), A085731(n), A181819(n), A373247(n)], for all i, j >= 1.

Original entry on oeis.org

1, 2, 3, 4, 3, 5, 3, 6, 7, 8, 3, 9, 3, 10, 11, 12, 3, 13, 3, 14, 15, 16, 3, 17, 18, 19, 20, 21, 3, 22, 3, 23, 24, 25, 26, 27, 3, 28, 29, 30, 3, 31, 3, 32, 33, 34, 3, 35, 36, 37, 38, 39, 3, 40, 29, 41, 42, 43, 3, 44, 3, 45, 46, 47, 48, 49, 3, 50, 51, 52, 3, 53, 3, 54, 55, 56, 48, 57, 3, 58, 59, 60, 3, 61, 42, 62, 63, 64, 3, 65, 38, 66, 67, 68, 69, 70, 3, 71, 72
Offset: 1

Views

Author

Antti Karttunen, Jun 24 2024

Keywords

Comments

Restricted growth sequence transform of the quadruple [A003415(n), A085731(n), A181819(n), A373247(n)].
For all i, j >= 1:
A305801(i) = A305801(j) => a(i) = a(j),
a(i) = a(j) => A300249(i) = A300249(j) => A101296(i) = A101296(j),
a(i) = a(j) => A369051(i) = A369051(j),
a(i) = a(j) => A373250(i) = A373250(j).

Crossrefs

Differs from A353520 and A361021 first at n=130, where a(130) = 82, while A353520(130) = A361021(130) = 96.

Programs

  • PARI
    up_to = 100000;
    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; };
    A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1]));
    A181819(n) = factorback(apply(e->prime(e),(factor(n)[,2])));
    Aux373980(n) = { my(d=A003415(n), s=A181819(n)); [d, s, gcd(n,d), n%s]; };
    v373980 = rgs_transform(vector(up_to, n, Aux373980(n)));
    A373980(n) = v373980[n];

A373981 Lexicographically earliest infinite sequence such that a(i) = a(j) => f(i) = f(j), where f(n) = [A107463(n), A181819(n), A373247(n)], for all i, j >= 1.

Original entry on oeis.org

1, 2, 3, 4, 3, 5, 3, 6, 7, 8, 3, 9, 3, 10, 11, 12, 3, 13, 3, 14, 15, 16, 3, 17, 18, 19, 20, 21, 3, 22, 3, 23, 24, 25, 26, 27, 3, 28, 29, 30, 3, 31, 3, 32, 33, 34, 3, 35, 36, 37, 38, 39, 3, 40, 29, 41, 42, 43, 3, 44, 3, 45, 46, 47, 48, 49, 3, 50, 51, 52, 3, 53, 3, 54, 46, 55, 48, 56, 3, 57, 58, 59, 3, 60, 42, 61, 62, 63, 3, 64, 38, 65, 66, 67, 68, 69, 3, 70, 71
Offset: 1

Views

Author

Antti Karttunen, Jun 24 2024

Keywords

Comments

Restricted growth sequence transform of the triple [A107463(n), A181819(n), A373247(n)].
For all i, j >= 1:
A305801(i) = A305801(j) => a(i) = a(j),
a(i) = a(j) => A373250(i) = A373250(j) => A101296(i) = A101296(j),
a(i) = a(j) => A373976(i) = A373976(j).

Crossrefs

Programs

  • PARI
    up_to = 100000;
    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; };
    A001414(n) = ((n=factor(n))[, 1]~*n[, 2]);
    A107463(n) = if(n<=1,n,if(isprime(n),1,A001414(n)));
    A181819(n) = factorback(apply(e->prime(e),(factor(n)[,2])));
    Aux373981(n) = { my(s=A181819(n)); [A107463(n), s, n%s]; };
    v373981 = rgs_transform(vector(up_to, n, Aux373981(n)));
    A373981(n) = v373981[n];

A373246 Greatest common divisor of n and its prime shadow: a(n) = gcd(n, A181819(n)).

Original entry on oeis.org

1, 2, 1, 1, 1, 2, 1, 1, 3, 2, 1, 6, 1, 2, 1, 1, 1, 6, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 1, 1, 2, 1, 9, 1, 2, 1, 10, 1, 2, 1, 2, 3, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 12, 1, 2, 3, 1, 1, 2, 1, 2, 1, 2, 1, 3, 1, 2, 3, 2, 1, 2, 1, 2, 1, 2, 1, 12, 1, 2, 1, 2, 1, 6, 1, 2, 1, 2, 1, 2, 1, 2, 3, 1, 1, 2, 1, 2, 1
Offset: 1

Views

Author

Antti Karttunen, May 29 2024

Keywords

Crossrefs

Cf. A325755 [numbers k for which a(k) = A181819(k)], A353566 (their characteristic function).

Programs

Formula

a(n) = gcd(A181819(n), A373247(n)).
a(n) = A181819(n) / A373249(n).

A373250 Lexicographically earliest infinite sequence such that a(i) = a(j) => A181819(i) = A181819(j) and i mod A181819(i) = j mod A181819(j), for all i, j >= 1, where A181819 is the prime shadow of n.

Original entry on oeis.org

1, 2, 3, 4, 3, 5, 3, 6, 7, 5, 3, 8, 3, 5, 9, 10, 3, 8, 3, 11, 12, 5, 3, 13, 4, 5, 14, 15, 3, 16, 3, 17, 12, 5, 9, 18, 3, 5, 9, 19, 3, 20, 3, 11, 21, 5, 3, 22, 4, 11, 9, 15, 3, 13, 9, 23, 12, 5, 3, 24, 3, 5, 21, 25, 12, 20, 3, 11, 12, 16, 3, 26, 3, 5, 21, 15, 12, 16, 3, 27, 28, 5, 3, 24, 12, 5, 9, 29, 3, 30, 9, 11, 12, 5, 9, 31, 3, 11, 21
Offset: 1

Views

Author

Antti Karttunen, May 30 2024

Keywords

Comments

Restricted growth sequence transform of the ordered pair [A181819(n), A373247(n)].
For all i, j:
A373251(i) = A373251(j) => a(i) = a(j),
a(i) = a(j) => A101296(i) = A101296(j),
a(i) = a(j) => A373246(i) = A373246(j),
a(i) = a(j) => A373249(i) = A373249(j),
a(i) = a(j) => A353566(i) = A353566(j).

Crossrefs

Programs

  • PARI
    up_to = 100000;
    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; };
    A181819(n) = factorback(apply(e->prime(e),(factor(n)[,2])));
    Aux373250(n) = [A181819(n), n%A181819(n)];
    v373250 = rgs_transform(vector(up_to, n, Aux373250(n)));
    A373250(n) = v373250[n];

A373251 Lexicographically earliest infinite sequence such that a(i) = a(j) => A181819(i) = A181819(j), i mod A181819(i) = j mod A181819(j), and gcd(i,A276086(i)) = gcd(j,A276086(j)), for all i, j >= 1, where A181819 is the prime shadow of n, and A276086 is the primorial base exp-function.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 5, 7, 8, 9, 5, 10, 5, 6, 11, 12, 5, 10, 5, 13, 14, 6, 5, 15, 16, 6, 17, 18, 5, 19, 5, 20, 14, 6, 21, 22, 5, 6, 23, 24, 5, 25, 5, 26, 27, 6, 5, 28, 29, 30, 23, 18, 5, 15, 31, 32, 14, 6, 5, 33, 5, 6, 34, 35, 36, 37, 5, 26, 14, 38, 5, 39, 5, 6, 40, 18, 41, 19, 5, 42, 43, 6, 5, 44, 45, 6, 23, 46, 5, 47, 21, 26, 14, 6
Offset: 1

Views

Author

Antti Karttunen, May 30 2024

Keywords

Comments

Restricted growth sequence transform of the triple [A181819(n), A373247(n), A324198(n)].
For all i, j:
A305900(i) = A305900(j) => a(i) = a(j),
a(i) = a(j) => A373248(i) = A373248(j),
a(i) = a(j) => A373250(i) = A373250(j).

Crossrefs

Programs

  • PARI
    up_to = 100000;
    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; };
    A181819(n) = factorback(apply(e->prime(e),(factor(n)[,2])));
    A324198(n) = { my(m=1, p=2, orgn=n); while(n, m *= (p^min(n%p, valuation(orgn, p))); n = n\p; p = nextprime(1+p)); (m); };
    Aux373251(n) = [A181819(n), n%A181819(n), A324198(n)];
    v373251 = rgs_transform(vector(up_to, n, Aux373251(n)));
    A373251(n) = v373251[n];
Showing 1-5 of 5 results.