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.

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A353520 Lexicographically earliest infinite sequence such that a(i) = a(j) => A003415(i) = A003415(j), A003557(i) = A003557(j) and A053669(i) = A053669(j), 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
Offset: 1

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Author

Antti Karttunen, Apr 25 2022

Keywords

Comments

Restricted growth sequence transform of the triplet [A003415(n), A003557(n), A053669(n)].
For all i, j:
A305801(i) = A305801(j) => a(i) = a(j),
a(i) = a(j) => A007814(i) = A007814(j),
a(i) = a(j) => A344025(i) = A344025(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; };
    A003415(n) = {my(fac); if(n<1, 0, fac=factor(n); sum(i=1, matsize(fac)[1], n*fac[i, 2]/fac[i, 1]))}; \\ From A003415
    A003557(n) = (n/factorback(factorint(n)[, 1]));
    A053669(n) = forprime(p=2, , if(n%p, return(p))); \\ From A053669
    Aux353520(n) = [A003415(n), A003557(n), A053669(n)];
    v353520 = rgs_transform(vector(up_to,n,Aux353520(n)));
    A353520(n) = v353520[n];

A319346 Filter sequence combining the sum of proper divisors (A001065) with the 2-adic valuation of n (A007814).

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, 20, 26, 3, 27, 28, 29, 3, 30, 3, 31, 32, 33, 3, 34, 35, 36, 37, 38, 3, 39, 28, 40, 41, 42, 3, 43, 3, 44, 45, 46, 47, 48, 3, 49, 50, 51, 3, 52, 3, 53, 54, 55, 47, 56, 3, 57, 58, 59, 3, 60, 41, 61, 32, 62, 3, 63, 37, 64, 65, 66, 67, 68, 3, 69
Offset: 1

Views

Author

Antti Karttunen, Sep 24 2018

Keywords

Comments

Restricted growth sequence transform of ordered pair [A001065(n), A007814(n)].

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; };
    A001065(n) = (sigma(n)-n);
    A007814(n) = valuation(n,2);
    v319346 = rgs_transform(vector(up_to,n,[A001065(n),A007814(n)]));
    A319346(n) = v319346[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

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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.

A323369 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) = A323368(n) for any other number.

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, 24, 26, 3, 27, 28, 29, 3, 30, 3, 31, 32, 22, 3, 33, 34, 35, 36, 37, 3, 38, 36, 39, 40, 41, 3, 42, 3, 30, 43, 44, 45, 46, 3, 47, 48, 46, 3, 49, 3, 50, 51, 52, 48, 53, 3, 54, 55, 56, 3, 57, 58, 59, 60, 61, 3, 62, 63, 42, 64, 46, 60, 65, 3, 66, 67, 68, 3, 69, 3
Offset: 1

Views

Author

Antti Karttunen, Jan 12 2019

Keywords

Comments

Restricted growth sequence transform of function f, where f(n) = 0 for odd primes, and for any other number, f(n) = [A000035(n), A003557(n), A048250(n)].
For all i, j:
A305801(i) = A305801(j) => a(i) = a(j),
a(i) = a(j) => A007814(i) = A007814(j),
a(i) = a(j) => A322588(i) = A322588(j),
a(i) = a(j) => A323238(i) = A323238(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]));
    Aux323369(n) = if((n>2)&&isprime(n),0,[(n%2), A003557(n), A048250(n)]);
    v323369 = rgs_transform(vector(up_to, n, Aux323369(n)));
    A323369(n) = v323369[n];

A323405 Lexicographically earliest sequence such that for all i, j, a(i) = a(j) => f(i) = f(j) where f(n) = [A003557(n), A023900(n), A063994(n)] for all other numbers, except f(n) = 0 for odd primes.

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, 26, 29, 3, 30, 3, 31, 32, 33, 3, 34, 35, 36, 37, 38, 3, 39, 40, 41, 42, 43, 3, 44, 3, 45, 46, 47, 48, 49, 3, 50, 51, 52, 3, 53, 3, 54, 55, 56, 57, 58, 3, 59, 60, 61, 3, 62, 63, 64, 65, 66, 3, 67, 68, 69, 57, 70, 71, 72, 3, 73, 74, 75, 3
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) => A323371(i) = A323371(j),
a(i) = a(j) => A247074(i) = A247074(j).

Crossrefs

Differs from A323370 for the first time at n=78, where a(78) = 58, while A323370(78) = 52.
Cf. also A323374.

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] = max(0,f[i, 2]-1)); factorback(f); };
    A023900(n) = sumdivmult(n, d, d*moebius(d)); \\ From A023900
    A063994(n) = { my(f=factor(n)[, 1]); prod(i=1, #f, gcd(f[i]-1, n-1)); }; \\ From A063994
    Aux323405(n) = if((n>2)&&isprime(n),0,[A003557(n), A023900(n), A063994(n)]);
    v323405 = rgs_transform(vector(up_to, n, Aux323405(n)));
    A323405(n) = v323405[n];

A322816 Lexicographically earliest sequence such that a(i) = a(j) => f(i) = f(j) for all i, j, where f(n) = A048675(n) for all other numbers, except f(n) = -1 if n is an odd prime.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Dec 27 2018

Keywords

Comments

For all i, j > 1:
A323078(i) = A323078(j) => a(i) = a(j),
a(i) = a(j) => A322812(i) = A322812(j),
a(i) = a(j) => A322869(i) = A322869(j).

Crossrefs

Programs

  • PARI
    up_to = 4096;
    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; };
    A048675(n) = my(f = factor(n)); sum(k=1, #f~, f[k, 2]*2^primepi(f[k, 1]))/2; \\ From A048675
    A322816aux(n) = if((n>2)&&isprime(n),-1,A048675(n));
    v322816 = rgs_transform(vector(up_to,n,A322816aux(n)));
    A322816(n) = v322816[n];

A323367 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) = A323366(n) for any other number.

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, 26, 29, 3, 19, 3, 30, 31, 32, 3, 33, 34, 35, 36, 37, 3, 38, 39, 40, 41, 42, 3, 43, 3, 44, 45, 46, 47, 48, 3, 49, 50, 51, 3, 52, 3, 53, 54, 55, 56, 51, 3, 57, 58, 59, 3, 37, 60, 61, 62, 63, 3, 64, 65, 66, 56, 67, 65, 68, 3, 69, 70, 71, 3, 72, 3, 73, 47
Offset: 1

Views

Author

Antti Karttunen, Jan 12 2019

Keywords

Comments

Restricted growth sequence transform of function f, where f(n) = 0 for odd primes, and for any other number, f(n) = [A000035(n), A003557(n), A173557(n)].
For all i, j:
A305801(i) = A305801(j) => a(i) = a(j),
a(i) = a(j) => A007814(i) = A007814(j),
a(i) = a(j) => A322587(i) = A322587(j).
a(i) = a(j) => A323237(i) = A323237(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
    Aux323367(n) = if((n>2)&&isprime(n),0,[(n%2), A003557(n), A173557(n)]);
    v323367 = rgs_transform(vector(up_to, n, Aux323367(n)));
    A323367(n) = v323367[n];

A323370 Lexicographically earliest sequence such that for all i, j, a(i) = a(j) => f(i) = f(j) where f(n) = [A000035(n), A003557(n), A023900(n)] for all other numbers, except f(n) = 0 for odd primes.

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, 26, 29, 3, 30, 3, 31, 32, 33, 3, 34, 35, 36, 37, 38, 3, 39, 40, 41, 42, 43, 3, 44, 3, 45, 46, 47, 48, 49, 3, 50, 51, 52, 3, 53, 3, 54, 55, 56, 57, 52, 3, 58, 59, 60, 3, 61, 62, 63, 64, 65, 3, 66, 67, 68, 57, 69, 67, 70, 3, 71, 72, 73, 3, 74, 3, 75, 76
Offset: 1

Views

Author

Antti Karttunen, Jan 13 2019

Keywords

Comments

Restricted growth sequence transform of function f, defined as f(n) = 0 when n is an odd prime, and f(n) = [A000035(n), A003557(n), A023900(n)] for all other numbers.
For all i, j:
A305801(i) = A305801(j) => a(i) = a(j),
a(i) = a(j) => A323367(i) = A323367(j),
a(i) = a(j) => A323371(i) = A323371(j).

Crossrefs

Differs from A323405 for the first time at n=78, where a(78) = 52, while A323405(78) = 58.

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] = max(0,f[i, 2]-1)); factorback(f); };
    A023900(n) = sumdivmult(n, d, d*moebius(d)); \\ From A023900
    Aux323370(n) = if((n>2)&&isprime(n),0,[(n%2), A003557(n), A023900(n)]);
    v323370 = rgs_transform(vector(up_to, n, Aux323370(n)));
    A323370(n) = v323370[n];

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];

A329608 Lexicographically earliest infinite sequence such that a(i) = a(j) => f(i) = f(j), where f(n) = A329605(n) for all other n, except for odd primes p, f(p) = 0.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Nov 18 2019

Keywords

Comments

For all i, j:
A305801(i) = A305801(j) => a(i) = a(j) => A329614(i) = A329614(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; };
    A034386(n) = prod(i=1, primepi(n), prime(i));
    A108951(n) = { my(f=factor(n)); prod(i=1, #f~, A034386(f[i, 1])^f[i, 2]) };  \\ From A108951
    A329605(n) = numdiv(A108951(n));
    Aux329608(n) = if((n%2)&&isprime(n),0,A329605(n));
    v329608 = rgs_transform(vector(up_to, n, Aux329608(n)));
    A329608(n) = v329608[n];
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