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 1-7 of 7 results.

A329896 Lexicographically earliest infinite sequence such that a(i) = a(j) => A219175(i) = A219175(j) and A322592(i) = A322592(j) for all i, j.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Dec 07 2019

Keywords

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; };
    A219175(n) = (n%lcm(znstar(n)[2]));
    A289625(n) = { my(m=1,p=2,v=znstar(n)[2]); for(i=1,length(v),m *= p^v[i]; p = nextprime(p+1)); (m); };
    Aux329896(n) = if((n>2)&&isprime(n),0,[A219175(n),A289625(n)]);
    v329896 = rgs_transform(vector(up_to, n, Aux329896(n)));
    A329896(n) = v329896[n];

A322587 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 f(n) = A291756(n) [equally: A295887(n)] for any other number.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Dec 18 2018

Keywords

Comments

For all i, j: a(i) = a(j) => A322320(i) = A322320(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; };
    A003557(n) = { my(f=factor(n)); for(i=1, #f~, f[i, 2] = f[i, 2]-1); factorback(f); };
    A173557(n) = my(f=factor(n)[, 1]); prod(k=1, #f, f[k]-1); \\ From A173557
    Aux322587(n) = if((n>2)&&isprime(n),0,(1/2)*(2 + ((A003557(n)+A173557(n))^2) - A003557(n) - 3*A173557(n)));
    v322587 = rgs_transform(vector(up_to, n, Aux322587(n)));
    A322587(n) = v322587[n];

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

Views

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];

A322588 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 f(n) = A291750(n) for any other number.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Dec 18 2018

Keywords

Comments

For all i, j: a(i) = a(j) => A322318(i) = A322318(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; };
    A003557(n) = { my(f=factor(n)); for(i=1, #f~, f[i, 2] = f[i, 2]-1); factorback(f); };
    A048250(n) = factorback(apply(p -> p+1,factor(n)[,1]));
    Aux322588(n) = if((n>2)&&isprime(n),0,(1/2)*(2 + ((A003557(n)+A048250(n))^2) - A003557(n) - 3*A048250(n)));
    v322588 = rgs_transform(vector(up_to, n, Aux322588(n)));
    A322588(n) = v322588[n];

A322589 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 f(n) = A007913(n) for any other number.

Original entry on oeis.org

1, 2, 3, 1, 3, 4, 3, 2, 1, 5, 3, 6, 3, 7, 8, 1, 3, 2, 3, 9, 10, 11, 3, 4, 1, 12, 6, 13, 3, 14, 3, 2, 15, 16, 17, 1, 3, 18, 19, 5, 3, 20, 3, 21, 9, 22, 3, 6, 1, 2, 23, 24, 3, 4, 25, 7, 26, 27, 3, 8, 3, 28, 13, 1, 29, 30, 3, 31, 32, 33, 3, 2, 3, 34, 6, 35, 36, 37, 3, 9, 1, 38, 3, 10, 39, 40, 41, 11, 3, 5, 42, 43, 44, 45, 46, 4, 3, 2, 21, 1, 3, 47, 3, 12, 48
Offset: 1

Views

Author

Antti Karttunen, Dec 18 2018

Keywords

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; };
    Aux322589(n) = if((n>2)&&isprime(n),0,core(n));
    v322589 = rgs_transform(vector(up_to, n, Aux322589(n)));
    A322589(n) = v322589[n];

A322809 Lexicographically earliest such sequence a that a(i) = a(j) => f(i) = f(j) for all i, j, where f(n) = -1 if n is an odd prime, and f(n) = floor(n/2) for all other numbers.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Dec 26 2018

Keywords

Comments

This sequence is a restricted growth sequence transform of a function f which is defined as f(n) = A004526(n), unless n is an odd prime, in which case f(n) = -1, which is a constant not in range of A004526. See the Crossrefs section for a list of similar sequences.
For all i, j:
A305801(i) = A305801(j) => a(i) = a(j),
a(i) = a(j) => A039636(i) = A039636(j).
For all i, j: a(i) = a(j) <=> A323161(i+1) = A323161(j+1).
The shifted version of this filter, A323161, has a remarkable ability to find many sequences related to primes and prime chains. - Antti Karttunen, Jan 06 2019

Crossrefs

A list of few similarly constructed sequences follows, where each sequence is an rgs-transform of such function f, for which the value of f(n) is the n-th term of the sequence whose A-number follows after a parenthesis, unless n is of the form ..., in which case f(n) is given a constant value outside of the range of that sequence:
A322809 (A004526, unless an odd prime) [This sequence],
A322589 (A007913, unless an odd prime),
A322591 (A007947, unless an odd prime),
A322805 (A252463, unless an odd prime),
A323082 (A300840, unless an odd prime),
A322822 (A300840, unless n > 2 and a Fermi-Dirac prime, A050376),
A322988 (A322990, unless a prime power > 2),
A323078 (A097246, unless an odd prime),
A322808 (A097246, unless a squarefree number > 2),
A322816 (A048675, unless an odd prime),
A322807 (A285330, unless an odd prime),
A322814 (A286621, unless an odd prime),
A322824 (A242424, unless an odd prime),
A322973 (A006370, unless an odd prime),
A322974 (A049820, unless n > 1 and n is in A046642),
A323079 (A060681, unless an odd prime),
A322587 (A295887, unless an odd prime),
A322588 (A291751, unless an odd prime),
A322592 (A289625, unless an odd prime),
A323369 (A323368, unless an odd prime),
A323371 (A295886, unless an odd prime),
A323374 (A323373, unless an odd prime),
A323401 (A323372, unless an odd prime),
A323405 (A323404, unless an odd prime).

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; };
    A322809aux(n) = if((n>2)&&isprime(n),-1,(n>>1));
    v322809 = rgs_transform(vector(up_to,n,A322809aux(n)));
    A322809(n) = v322809[n];

Formula

a(n) = A323161(n+1) - 1.

A323374 Lexicographically earliest sequence such that for all i, j, a(i) = a(j) => f(i) = f(j) where f(n) = A323373(n) for all other numbers, except f(p) = -(p mod 2) for primes p.

Original entry on oeis.org

1, 2, 3, 4, 3, 4, 3, 5, 6, 5, 3, 5, 3, 7, 8, 9, 3, 7, 3, 9, 10, 11, 3, 9, 12, 13, 14, 15, 3, 9, 3, 16, 12, 16, 17, 13, 3, 18, 17, 16, 3, 13, 3, 19, 20, 21, 3, 16, 22, 19, 23, 24, 3, 18, 25, 26, 27, 28, 3, 16, 3, 29, 30, 31, 32, 33, 3, 31, 34, 24, 3, 26, 3, 35, 25, 36, 37, 26, 3, 31, 38, 39, 3, 26, 40, 41, 42, 39, 3, 26, 43, 44, 37, 45, 46, 31, 3, 41, 47, 39, 3, 31, 3, 48
Offset: 1

Views

Author

Antti Karttunen, Jan 13 2019

Keywords

Comments

For all i, j:
A305801(i) = A305801(j) => a(i) = a(j),
a(i) = a(j) => A039651(i) = A039651(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; };
    A049559(n) = gcd(eulerphi(n), n-1);
    A160595(n) = if(1==n, n, numerator(eulerphi(n)/(n-1)));
    Aux323374(n) = if(isprime(n),-(n%2),[A049559(n), A160595(n)]);
    v323374 = rgs_transform(vector(up_to, n, Aux323374(n)));
    A323374(n) = v323374[n];
Showing 1-7 of 7 results.