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 1-6 of 6 results.

A336158 The least number with the prime signature of the odd part of n: a(n) = A046523(A000265(n)).

Original entry on oeis.org

1, 1, 2, 1, 2, 2, 2, 1, 4, 2, 2, 2, 2, 2, 6, 1, 2, 4, 2, 2, 6, 2, 2, 2, 4, 2, 8, 2, 2, 6, 2, 1, 6, 2, 6, 4, 2, 2, 6, 2, 2, 6, 2, 2, 12, 2, 2, 2, 4, 4, 6, 2, 2, 8, 6, 2, 6, 2, 2, 6, 2, 2, 12, 1, 6, 6, 2, 2, 6, 6, 2, 4, 2, 2, 12, 2, 6, 6, 2, 2, 16, 2, 2, 6, 6, 2, 6, 2, 2, 12, 6, 2, 6, 2, 6, 2, 2, 4, 12, 4, 2, 6, 2, 2, 30
Offset: 1

Views

Author

Antti Karttunen, Jul 11 2020

Keywords

Crossrefs

Programs

  • PARI
    A000265(n) = (n>>valuation(n,2));
    A046523(n) = { my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]); };  \\ From A046523
    A336158(n) = A046523(A000265(n));
    
  • Python
    from math import prod
    from sympy import factorint, prime
    def A336158(n): return prod(prime(i+1)**e for i,e in enumerate(sorted(factorint(n>>(~n&n-1).bit_length()).values(),reverse=True))) # Chai Wah Wu, Sep 16 2022

Formula

a(n) = A046523(A000265(n)) = A046523(A064989(n)).
A000005(a(n)) = A001227(n).
A001221(a(n)) = A005087(n).
A001222(a(n)) = A087436(n).

A336159 Lexicographically earliest infinite sequence such that a(i) = a(j) => A278222(i) = A278222(j) and A336158(i) = A336158(j), for all i, j >= 1.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Jul 11 2020

Keywords

Comments

Restricted growth sequence transform of the ordered pair [A278222(n), A336158(n)], i.e., of the ordered pair [A046523(A005940(1+n)), A046523(A000265(n))].
For all i, j: A324400(i) = A324400(j) => A003602(i) = A003602(j) => a(i) = a(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; };
    A000265(n) = (n>>valuation(n,2));
    A005940(n) = { my(p=2, t=1); n--; until(!n\=2, if((n%2), (t*=p), p=nextprime(p+1))); (t); };
    A046523(n) = { my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]); };  \\ From A046523
    A278222(n) = A046523(A005940(1+n));
    A336158(n) = A046523(A000265(n));
    Aux336159(n) = [A278222(n), A336158(n)];
    v336159 = rgs_transform(vector(up_to, n, Aux336159(n)));
    A336159(n) = v336159[n];

A336155 Lexicographically earliest infinite sequence such that a(i) = a(j) => A007814(1+i) = A007814(1+j) and A335915(i) = A335915(j), for all i, j >= 1.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Jul 11 2020

Keywords

Comments

Restricted growth sequence transform of the ordered pair [A007814(1+n), A335915(n)]. Note that A007814(1+n) gives the number of trailing 1-bits in the binary expansion of n.
For all i, j: A324400(i) = A324400(j) => a(i) = a(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; };
    A007814(n) = valuation(n,2);
    A000265(n) = (n>>valuation(n,2));
    A335915(n) = { my(f=factor(n)); prod(k=1,#f~,if(2==f[k,1],1,(A000265(f[k,1]-1)*A000265(f[k,1]+1))^f[k,2])); };
    Aux336155(n) = [A007814(1+n), A335915(n)];
    v336155 = rgs_transform(vector(up_to, n, Aux336155(n)));
    A336155(n) = v336155[n];

A336152 Lexicographically earliest infinite sequence such that a(i) = a(j) => A001221(i) = A001221(j) and A007814(1+i) = A007814(1+j), for all i, j >= 1.

Original entry on oeis.org

1, 2, 3, 2, 4, 5, 6, 2, 4, 5, 3, 5, 4, 5, 7, 2, 4, 5, 3, 5, 8, 5, 6, 5, 4, 5, 3, 5, 4, 9, 10, 2, 8, 5, 11, 5, 4, 5, 12, 5, 4, 9, 3, 5, 8, 5, 13, 5, 4, 5, 11, 5, 4, 5, 12, 5, 8, 5, 3, 9, 4, 5, 14, 2, 8, 9, 3, 5, 8, 9, 6, 5, 4, 5, 11, 5, 8, 9, 13, 5, 4, 5, 3, 9, 8, 5, 12, 5, 4, 9, 11, 5, 8, 5, 15, 5, 4, 5, 11, 5, 4, 9, 6, 5, 16
Offset: 1

Views

Author

Antti Karttunen, Jul 11 2020

Keywords

Comments

Restricted growth sequence transform of the ordered pair [A001221(n), A007814(1+n)]. The first member of pair gives the number of distinct prime divisors of n, and the second member gives the number of trailing 1-bits in its binary expansion.
For all i, j: A324400(i) = A324400(j) => a(i) = a(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; };
    A007814(n) = valuation(n,2);
    Aux336152(n) = [omega(n), A007814(1+n)];
    v336152 = rgs_transform(vector(up_to, n, Aux336152(n)));
    A336152(n) = v336152[n];

A336154 Lexicographically earliest infinite sequence such that a(i) = a(j) => A007814(1+i) = A007814(1+j) and A278222(i) = A278222(j), for all i, j >= 1.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Jul 11 2020

Keywords

Comments

Restricted growth sequence transform of the ordered pair [A007814(1+n), A278222(n)]. Note that A007814(1+n) gives the number of trailing 1-bits in the binary expansion of n.
For all i, j: A324400(i) = A324400(j) => a(i) = a(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; };
    A007814(n) = valuation(n,2);
    A005940(n) = { my(p=2, t=1); n--; until(!n\=2, if((n%2), (t*=p), p=nextprime(p+1))); (t); };
    A046523(n) = { my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]); };  \\ From A046523
    A278222(n) = A046523(A005940(1+n));
    Aux336154(n) = [A007814(1+n), A278222(n)];
    v336154 = rgs_transform(vector(up_to, n, Aux336154(n)));
    A336154(n) = v336154[n];

A336153 Lexicographically earliest infinite sequence such that a(i) = a(j) => A007814(1+i) = A007814(1+j) and A009194(i) = A009194(j), for all i, j >= 1.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Jul 11 2020

Keywords

Comments

Restricted growth sequence transform of the ordered pair [A007814(1+n), A009194(n)]. Note that A007814(1+n) gives the number of trailing 1-bits in the binary expansion of n.
For all i, j: A324400(i) = A324400(j) => a(i) = a(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; };
    A007814(n) = valuation(n,2);
    A009194(n) = gcd(n, sigma(n));
    Aux336153(n) = [A007814(1+n), A009194(n)];
    v336153 = rgs_transform(vector(up_to, n, Aux336153(n)));
    A336153(n) = v336153[n];
Showing 1-6 of 6 results.