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 1-10 of 15 results. Next

A323241 Lexicographically earliest sequence such that a(i) = a(j) => f(i) = f(j) for all i, j, where f(n<=2) = -n, f(n) = 0 if n is an odd number > 1, and f(n) = A300226(n) for even numbers >= 4.

Original entry on oeis.org

1, 2, 3, 4, 3, 5, 3, 6, 3, 5, 3, 7, 3, 5, 3, 8, 3, 9, 3, 7, 3, 5, 3, 10, 3, 5, 3, 7, 3, 11, 3, 12, 3, 5, 3, 13, 3, 5, 3, 10, 3, 11, 3, 7, 3, 5, 3, 14, 3, 15, 3, 7, 3, 16, 3, 10, 3, 5, 3, 17, 3, 5, 3, 18, 3, 11, 3, 7, 3, 19, 3, 20, 3, 5, 3, 7, 3, 11, 3, 14, 3, 5, 3, 17, 3, 5, 3, 10, 3, 21, 3, 7, 3, 5, 3, 22, 3, 23, 3, 24, 3, 11, 3, 10, 3
Offset: 1

Views

Author

Antti Karttunen, Jan 07 2019

Keywords

Comments

For all i, j:
A319701(i) = A319701(j) => a(i) = a(j),
a(i) = a(j) => A007814(i) = A007814(j).
a(i) = a(j) => A183063(i) = A183063(j).

Links

Crossrefs

Cf. A007814, A052126, A183063, A300226, A319701, A319988, A323235, A323237, A323238, A323242.

Programs

  • PARI
    up_to = 10000;
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; };
A052126(n) = if(1==n, n, n/vecmax(factor(n)[, 1]));
A319988(n) = ((n>1)&&(factor(n)[omega(n),2]>1));
A323241aux(n) = if(n<=2,-n,if(n%2,0,[A052126(n), A319988(n)]));
v323241 = rgs_transform(vector(up_to,n,A323241aux(n)));
A323241(n) = v323241[n];

A323242 Lexicographically earliest sequence such that a(i) = a(j) => f(i) = f(j) for all i, j, where f(n<=2) = -n, f(n) = 0 if n is an even number > 2, and f(n) = A300226(n) for odd numbers >= 3.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Jan 07 2019

Keywords

Links

Crossrefs

Cf. A052126, A300226, A319701, A319988, A323241.

Programs

  • PARI
    up_to = 10000;
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; };
A052126(n) = if(1==n, n, n/vecmax(factor(n)[, 1]));
A319988(n) = ((n>1)&&(factor(n)[omega(n),2]>1));
A323242aux(n) = if(n<=2,-n,if(!(n%2),0,[A052126(n), A319988(n)]));
v323242 = rgs_transform(vector(up_to,n,A323242aux(n)));
A323242(n) = v323242[n];

A300235 Restricted growth sequence transform of A291765, filter combining A001065(n) and A046523(n), the sum of proper divisors and the prime signature of n.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Mar 01 2018

Keywords

Examples

			a(51) = a(91) (= 33) because both are nonsquare semiprimes (3*17 and 7*13), and the sum of their proper divisors (A001065) are equal 1+3+17 = 1+7+13 = 21.

Links

Crossrefs

Cf. A001065, A046523, A291765.
Cf. also A295885, A300223, A300226, A300229, A300230, A300231, A300232, A300233.

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; };
write_to_bfile(start_offset,vec,bfilename) = { for(n=1, length(vec), write(bfilename, (n+start_offset)-1, " ", vec[n])); }
A001065(n) = (sigma(n)-n);
A046523(n) = { my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]); };  \\ This function from Charles R Greathouse IV, Aug 17 2011
A291765(n) = (1/2)*(2 + ((A001065(n)+A046523(n))^2) - A001065(n) - 3*A046523(n));
write_to_bfile(1,rgs_transform(vector(up_to,n,A291765(n))),"b300235.txt");

A300230 Restricted growth sequence transform of A286570, combining A009194(n) and A046523(n), i.e., gcd(n,sigma(n)) and the prime signature of n.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Mar 01 2018

Keywords

Links

Crossrefs

Cf. A009194, A046523, A286570.
Cf. also A300223, A300226, A300229, A300231, A300232, A300233, A300235.

Programs

  • PARI
    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; };
write_to_bfile(start_offset,vec,bfilename) = { for(n=1, length(vec), write(bfilename, (n+start_offset)-1, " ", vec[n])); }
A009194(n) = gcd(n, sigma(n));
A046523(n) = { my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]); };  \\ This function from A046523
A286570(n) = (1/2)*(2 + ((A046523(n)+A009194(n))^2) - A046523(n) - 3*A009194(n));
write_to_bfile(1,rgs_transform(vector(65537,n,A286570(n))),"b300230.txt");

A300229 Restricted growth sequence transform of A285729, combining A032742(n) and A046523(n), the largest proper divisor and the prime signature of n.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Mar 01 2018

Keywords

Examples

			a(10) = a(15) (= 7) because both are nonsquare semiprimes (2*5 and 3*5), and when the smallest prime factor is divided out, both yield the same quotient, 5.

Links

Crossrefs

Cf. A032742, A046523, A285729.
Cf. also A300223, A300226, A300230, A300231, A300232, A300233, A300235.

Programs

  • PARI
    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; };
write_to_bfile(start_offset,vec,bfilename) = { for(n=1, length(vec), write(bfilename, (n+start_offset)-1, " ", vec[n])); }
A032742(n) = if(1==n,n,n/vecmin(factor(n)[,1]));
A046523(n) = { my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]); };  \\ From A046523
A285729(n) = (1/2)*(2 + ((A032742(n)+A046523(n))^2) - A032742(n) - 3*A046523(n));
write_to_bfile(1,rgs_transform(vector(65537,n,A285729(n))),"b300229.txt");

A300249 Filter sequence combining A003415(n) and A046523(n), the arithmetic derivative of n and the prime signature of n.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Mar 04 2018

Keywords

Comments

Restricted growth sequence transform of P(A003415(n), A046523(n)), where P(a,b) is a two-argument form of A000027 used as a Cantor pairing function N x N -> N.

Examples

			a(51) = a(91) (= 33) because both are nonsquare semiprimes (3*17 and 7*13), and also their arithmetic derivatives are equal, as A003415(51) = A003415(91) = 20.
a(78) = a(105) (= 56) because both have the same prime signature (78 = 2*3*13 and 105 = 3*5*7), and also their arithmetic derivatives are equal, as A003415(78) = A003415(105) = 71.

Links

Crossrefs

Cf. A003415, A046523.
Cf. also A300226, A300229, A300248.
Differs from A300235 for the first time at n=105, where a(105)=56, while A300235(105)=75.

Programs

  • PARI
    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; };
write_to_bfile(start_offset,vec,bfilename) = { for(n=1, length(vec), write(bfilename, (n+start_offset)-1, " ", vec[n])); }
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
A046523(n) = my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]) \\ From A046523
Aux300249(n) = ((1/2)*(2 + ((A003415(n)+A046523(n))^2) - A003415(n) - 3*A046523(n)));
write_to_bfile(1,rgs_transform(vector(65537,n,Aux300248(n))),"b300249.txt");

A300231 Filter sequence combining A001065(n) and A009194(n), the sum of proper divisors of n and gcd(n,sigma(n)).

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Mar 01 2018

Keywords

Comments

Restricted growth sequence transform of P(A001065(n), A009194(n)), where P(a,b) is a two-argument form of A000027 used as a Cantor pairing function N x N -> N.

Examples

			a(27) = a(35) (= 19) because A001065(27) = A001065(35) = 13 and A009194(27) = A009194(35) = 1.

Links

Crossrefs

Cf. A001065, A009194.
Cf. also A295885, A300223, A300226, A300229, A300230, A300232, A300233, A300235.

Programs

  • PARI
    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; };
write_to_bfile(start_offset,vec,bfilename) = { for(n=1, length(vec), write(bfilename, (n+start_offset)-1, " ", vec[n])); }
A001065(n) = (sigma(n)-n);
A009194(n) = gcd(n, sigma(n));
Aux300231(n) = (1/2)*(2 + ((A001065(n)+A009194(n))^2) - A001065(n) - 3*A009194(n));
write_to_bfile(1,rgs_transform(vector(65537,n,Aux300231(n))),"b300231.txt");

A300232 Restricted growth sequence transform of A286152, filter combining A051953(n) and A046523(n), cototient and the prime signature of n.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Mar 01 2018

Keywords

Examples

			a(39) = a(55) (= 27) because both are nonsquare semiprimes (3*13 and 5*11), and both have cototient value 15 = 39 - phi(39) = 55 - phi(55).

Links

Crossrefs

Cf. A046523, A051953, A286152.
Cf. also A295885, A300223, A300224, A300226, A300229, A300230, A300231, A300233, A300235.

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; };
write_to_bfile(start_offset,vec,bfilename) = { for(n=1, length(vec), write(bfilename, (n+start_offset)-1, " ", vec[n])); }
A051953(n) = (n - eulerphi(n));
A046523(n) = { my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]); };  \\ This function from Charles R Greathouse IV, Aug 17 2011
A286152(n) = (2 + ((A051953(n)+A046523(n))^2) - A051953(n) - 3*A046523(n))/2;
write_to_bfile(1,rgs_transform(vector(up_to,n,A286152(n))),"b300232.txt");

A300233 Filter sequence combining A051953(n) and A009194(n), cototient of n and gcd(n,sigma(n)).

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Mar 01 2018

Keywords

Comments

Restricted growth sequence transform of P(A051953(n), A009194(n)), where P(a,b) is a two-argument form of A000027 used as a Cantor pairing function N x N -> N.

Examples

			a(20) = a(22) (= 13) because A051953(20) = A051953(22) = 12 and A009194(20) = A009194(22) = 2.

Links

Crossrefs

Cf. A009194, A051953.
Cf. also A295885, A300223, A300226, A300229, A300230, A300231, A300232, A300235.

Programs

  • PARI
    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; };
write_to_bfile(start_offset,vec,bfilename) = { for(n=1, length(vec), write(bfilename, (n+start_offset)-1, " ", vec[n])); }
A009194(n) = gcd(n, sigma(n));
A051953(n) = (n - eulerphi(n));
Aux300233(n) = (1/2)*(2 + ((A051953(n)+A009194(n))^2) - A051953(n) - 3*A009194(n));
write_to_bfile(1,rgs_transform(vector(65537,n,Aux300233(n))),"b300233.txt");

A322826 Lexicographically earliest such sequence a that a(i) = a(j) => A052126(i) = A052126(j) for all i, j.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Dec 27 2018

Keywords

Comments

Restricted growth sequence transform of A052126, or equally, of A322820.
For all i, j:
A300226(i) = A300226(j) => a(i) = a(j),
a(i) = a(j) => A322813(i) = A322813(j),
a(i) = a(j) => A322819(i) = A322819(j).
For all i, j > 1:
a(i) = a(j) => A001222(i) = A001222(j).

Links

Crossrefs

Cf. A001222, A006530, A052126, A305800, A300226, A319994, A319996, A322813, A322819, A322820.

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; };
A006530(n) = if(n>1, vecmax(factor(n)[, 1]), 1);
A052126(n) = (n/A006530(n));
v322826 = rgs_transform(vector(up_to,n,A052126(n)));
A322826(n) = v322826[n];
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