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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A305976 Filter sequence for a(prime^k) = constant sequences.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Jul 02 2018

Keywords

Crossrefs

Programs

  • PARI
    up_to = 100000;
    partialsums(f,up_to) = { my(v = vector(up_to), s=0); for(i=1,up_to,s += f(i); v[i] = s); (v); }
    v065515 = partialsums(n -> (omega(n)<=1), up_to);
    A065515(n) = v065515[n];
    A085970(n) = (n - A065515(n));
    A305976(n) = if(1==n,n,if(isprimepower(n),2,2+A085970(n)));

Formula

a(1) = 1, for n > 1, if A010055(n) = 1 [when n is in A246655], a(n) = 2, otherwise a(n) = 2+A085970(n) = running count from 3 onward.

A351260 Lexicographically earliest infinite sequence such that a(i) = a(j) => A003415(i) = A003415(j), A003557(i) = A003557(j) and A046523(i) = A046523(j), for all i, j >= 1.

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, 72, 2, 73, 2, 74, 56
Offset: 1

Views

Author

Antti Karttunen, Feb 06 2022

Keywords

Comments

Restricted growth sequence transform of the triplet [A003415(n), A003557(n), A046523(n)].
For all i, j >= 1:
A305800(i) = A305800(j) => a(i) = a(j),
a(i) = a(j) => A294877(i) = A294877(j),
a(i) = a(j) => A300249(i) = A300249(j),
a(i) = a(j) => A344025(i) = A344025(j).

Crossrefs

Differs from A300235, A305895 and A327931 for the first time at n=105, where a(105) = 56, while A300235(105) = A305895(105) = A327931(105) = 75.
Differs from A300249 for the first time at n=425, where a(425) = 299, while A300249(425) = 198.

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]));
    A046523(n) = { my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]); };  \\ From A046523
    Aux351260(n) = [A003415(n), A003557(n), A046523(n)];
    v351260 = rgs_transform(vector(up_to,n,Aux351260(n)));
    A351260(n) = v351260[n];

A369050 Lexicographically earliest infinite sequence such that a(i) = a(j) => f(i) = f(j), where f(1) = 1, and for n>1, f(n) = [A003415(n), A369049(n)], for all i, j >= 1.

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, 56, 57, 2, 58, 59, 60, 2, 61, 62, 63, 64, 65, 2, 66, 37
Offset: 1

Views

Author

Antti Karttunen, Jan 15 2024

Keywords

Comments

Restricted growth sequence transform of the function f defined as: f(1) = 1, and for n>1, f(n) = [A003415(n), A369049(n)].
For all i, j:
A305800(i) = A305800(j) => a(i) = a(j),
a(i) = a(j) => A344025(i) = A344025(j) => A369051(i) = A369051(j).

Crossrefs

Differs from A351260 for the first time at n=77, where a(77) = 56, while A351260(77) = 47.
Differs from A300833 for the first time at n=91, where a(91) = 37, while A300833(91) = 67.

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) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1]));
    A369049(n) = (n % A003415(n));
    Aux369050(n) = if(1==n,1,[A003415(n), A369049(n)]);
    v369050 = rgs_transform(vector(up_to, n, Aux369050(n)));
    A369050(n) = v369050[n];

A373982 Lexicographically earliest infinite sequence such that a(i) = a(j) => A278226(A328768(i)) = A278226(A328768(j)), for all i, j >= 0.

Original entry on oeis.org

1, 1, 2, 2, 3, 2, 4, 2, 3, 3, 5, 2, 6, 2, 7, 8, 4, 2, 9, 2, 7, 10, 11, 2, 10, 3, 5, 12, 13, 2, 11, 2, 10, 14, 15, 16, 8, 2, 10, 17, 18, 2, 19, 2, 20, 21, 22, 2, 23, 3, 24, 10, 25, 2, 20, 26, 17, 27, 28, 2, 29, 2, 7, 24, 16, 29, 30, 2, 20, 22, 31, 2, 32, 2, 33, 19, 34, 35, 36, 2, 11, 4, 37, 2, 22, 29, 11, 25, 38, 2, 33, 39, 17, 10, 40, 41, 10, 2, 42, 43, 20
Offset: 0

Views

Author

Antti Karttunen, Jun 25 2024

Keywords

Comments

Restricted growth sequence transform of A278226(A328768(n)).
For all i, j >= 1:
A305800(i) = A305800(j) => A373983(i) = A373983(j) => a(i) = a(j).
For all i, j >= 0: a(i) = a(j) => A328771(i) = A328771(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; };
    A046523(n) = { my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]); };  \\ From A046523
    A276086(n) = { my(m=1, p=2); while(n, m *= (p^(n%p)); n = n\p; p = nextprime(1+p)); (m); };
    A278226(n) = A046523(A276086(n));
    A002110(n) = prod(i=1,n,prime(i));
    A328768(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]*A002110(primepi(f[i,1])-1)/f[i, 1]));
    v373982 = rgs_transform(vector(1+up_to, n, A278226(A328768(n-1))));
    A373982(n) = v373982[1+n];

A305895 Filter sequence combining sum of proper divisors (A001065) and cototient (A051953) 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, 72, 2, 73, 2, 74, 75
Offset: 1

Views

Author

Antti Karttunen, Jun 14 2018

Keywords

Comments

Restricted growth sequence transform of ordered pair [A001065(n), A051953(n)].

Crossrefs

Differs from A300249 for the first time at n=105, where a(105) = 75, while A300249(105) = 56.
Differs from A300235 for the first time at n=153, where a(153) = 110, while A300235(153) = 106.

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);
    A051953(n) = (n-eulerphi(n));
    Aux305895(n) = [A001065(n), A051953(n)];
    v305895 = rgs_transform(vector(up_to,n,Aux305895(n)));
    A305895(n) = v305895[n];

Formula

a(1) = 1; for n > 1, a(n) = 1 + A295885(n).

A323888 Lexicographically earliest sequence such that for all i, j, a(i) = a(j) => f(i) = f(j) where f(n) = [A032742(n),A302042(n)] for all n > 1, with f(1) = 0.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Feb 08 2019

Keywords

Comments

For all i, j:
A305800(i) = A305800(j) => a(i) = a(j),
a(i) = a(j) => A001222(i) = A001222(j),
a(i) = a(j) => A253557(i) = A253557(j).

Crossrefs

Programs

  • PARI
    up_to = 65537;
    ordinal_transform(invec) = { my(om = Map(), outvec = vector(length(invec)), pt); for(i=1, length(invec), if(mapisdefined(om,invec[i]), pt = mapget(om, invec[i]), pt = 0); outvec[i] = (1+pt); mapput(om,invec[i],(1+pt))); outvec; };
    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; };
    A020639(n) = if(n>1, if(n>n=factor(n, 0)[1, 1], n, factor(n)[1, 1]), 1); \\ From A020639
    A032742(n) = (n/A020639(n));
    v078898 = ordinal_transform(vector(up_to,n,A020639(n)));
    A078898(n) = v078898[n];
    A302042(n) = if((1==n)||isprime(n),1,my(c = A078898(n), p = prime(-1+primepi(A020639(n))+primepi(A020639(c))), d = A078898(c), k=0); while(d, k++; if((1==k)||(A020639(k)>=p),d -= 1)); (k*p));
    A323888aux(n) = if(1==n, 0, [A032742(n),A302042(n)]);
    v323888 = rgs_transform(vector(up_to, n, A323888aux(n)));
    A323888(n) = v323888[n];

A329620 Lexicographically earliest infinite sequence such that a(i) = a(j) => f(i) = f(j), where f(n) = [A046523(n), A246277(A324886(n))].

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Nov 18 2019

Keywords

Comments

Restricted growth sequence transform of the ordered pair [A046523(n), A246277(A324886(n))].
For all i, j:
A305800(i) = A305800(j) => a(i) = a(j),
a(i) = a(j) => A101296(i) = A101296(j),
a(i) = a(j) => A329345(i) = A329345(j),
a(i) = a(j) => A329618(i) = A329618(j),
a(i) = a(j) => A329619(i) = A329619(j).

Crossrefs

Programs

  • PARI
    up_to = 8192;
    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; };
    A046523(n) = { my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]); }; \\ From A046523
    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
    A276086(n) = { my(m=1, p=2); while(n, m *= (p^(n%p)); n = n\p; p = nextprime(1+p)); (m); };
    A324886(n) = A276086(A108951(n));
    A246277(n) = if(1==n, 0, my(f = factor(n), k = primepi(f[1,1])-1); for (i=1, #f~, f[i,1] = prime(primepi(f[i,1])-k)); factorback(f)/2);
    Aux329620(n) = [A046523(n), A246277(A324886(n))];
    v329620 = rgs_transform(vector(up_to, n, Aux329620(n)));
    A329620(n) = v329620[n];

A351085 Lexicographically earliest infinite sequence such that a(i) = a(j) => A327858(i) = A327858(j) and A345000(i) = A345000(j) for all i, j >= 0.

Original entry on oeis.org

1, 2, 3, 3, 4, 3, 5, 3, 6, 7, 3, 3, 4, 3, 8, 2, 9, 3, 10, 3, 11, 12, 3, 3, 13, 12, 14, 8, 4, 3, 3, 3, 15, 16, 3, 17, 18, 3, 19, 2, 4, 3, 3, 3, 6, 8, 20, 3, 21, 16, 14, 12, 22, 3, 10, 2, 4, 2, 3, 3, 4, 3, 8, 8, 23, 24, 3, 3, 11, 2, 3, 3, 25, 3, 8, 26, 27, 24, 3, 3, 9, 7, 3, 3, 4, 2, 14, 2, 28, 3, 10, 2, 29, 2, 30
Offset: 0

Views

Author

Antti Karttunen, Feb 03 2022

Keywords

Comments

Restricted growth sequence transform of the ordered pair [A327858(n), A345000(n)].
For all i, j >= 1: A305800(i) = A305800(j) => a(i) = a(j).
For all i, j >= 0: a(i) = a(j) => A351086(i) = A351086(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
    A276086(n) = { my(m=1, p=2); while(n, m *= (p^(n%p)); n = n\p; p = nextprime(1+p)); (m); };
    A327858(n) = gcd(A003415(n),A276086(n));
    A345000(n) = gcd(A003415(n),A003415(A276086(n)));
    Aux351085(n) = [A327858(n), A345000(n)];
    v351085 = rgs_transform(vector(1+up_to,n,Aux351085(n-1)));
    A351085(n) = v351085[1+n];

A373150 Lexicographically earliest infinite sequence such that a(i) = a(j) => f(i) = f(j), where f(1) = 1, and for n>1, f(n) = [A003415(n), A085731(n), A373148(n)], for all i, j >= 1.

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, 56, 57, 2, 58, 59, 60, 2, 61, 62, 63, 64, 65, 2, 66, 67, 68, 69, 70, 71, 72, 2, 73, 74
Offset: 1

Views

Author

Antti Karttunen, May 27 2024

Keywords

Comments

Restricted growth sequence transform of the function f defined as: f(1) = 1, and for n>1, f(n) = [A003415(n), A085731(n), A373148(n)].
For all i, j >= 1:
A305800(i) = A305800(j) => a(i) = a(j),
a(i) = a(j) => A369051(i) = A369051(j),
a(i) = a(j) => A373151(i) = A373151(j) => A373143(i) = A373143(j).

Crossrefs

Differs from A369050 for the first time at n=91, where a(91)=67, while A369050(91)=37.
Differs from A300833 for the first time at n=133, where a(133)=133, while A300833(133)=50.

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]));
    A085731(n) = gcd(A003415(n),n);
    A002110(n) = prod(i=1,n,prime(i));
    A276085(n) = { my(f = factor(n)); sum(k=1, #f~, f[k, 2]*A002110(primepi(f[k, 1])-1)); };
    A373148(n) = (A276085(n)%A003415(n));
    Aux373150(n) = if(1==n,1,[A003415(n), A085731(n), A373148(n)]);
    v373150 = rgs_transform(vector(up_to, n, Aux373150(n)));
    A373150(n) = v373150[n];

A304103 Restricted growth sequence transform of A304102, a filter sequence related to the proper divisors of n expressed in Fibonacci number system.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, May 13 2018

Keywords

Comments

For all i, j: a(i) = a(j) => b(i) = b(j), where b can be any of {A000005, A293435, A304095 or A300836} for example.

Crossrefs

Cf. also A300835, A304105, A305800.
Cf. A305793 (analogous filter for base 2).

Programs

  • PARI
    \\ Needs also code from A304101.
    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])); }
    A304102(n) = { my(m=1); fordiv(n,d,if(dA304101(d)-1))); (m); };
    write_to_bfile(1,rgs_transform(vector(up_to,n,A304102(n))),"b304103.txt");
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