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.

Previous Showing 11-19 of 19 results.

A286605 Restricted growth sequence computed for number of divisors, d(n) (A000005).

Original entry on oeis.org

1, 2, 2, 3, 2, 4, 2, 4, 3, 4, 2, 5, 2, 4, 4, 6, 2, 5, 2, 5, 4, 4, 2, 7, 3, 4, 4, 5, 2, 7, 2, 5, 4, 4, 4, 8, 2, 4, 4, 7, 2, 7, 2, 5, 5, 4, 2, 9, 3, 5, 4, 5, 2, 7, 4, 7, 4, 4, 2, 10, 2, 4, 5, 11, 4, 7, 2, 5, 4, 7, 2, 10, 2, 4, 5, 5, 4, 7, 2, 9, 6, 4, 2, 10, 4, 4, 4, 7, 2, 10, 4, 5, 4, 4, 4, 10, 2, 5, 5, 8, 2, 7, 2, 7, 7, 4, 2, 10, 2, 7, 4, 9, 2, 7, 4, 5, 5, 4, 4
Offset: 1

Views

Author

Antti Karttunen, May 11 2017

Keywords

Comments

For all i, j: A101296(i) = A101296(j) => a(i) = a(j).
For all i, j: a(i) = a(j) <=> A000005(i) = A000005(j).

Crossrefs

Cf. A000005, A007416 (positions of records, and also the first occurrence of each n).

Programs

  • Mathematica
    With[{nn = 119}, Function[s, Table[Position[Keys@ s, k_ /; MemberQ[k, n]][[1, 1]], {n, nn}]]@ Map[#1 -> #2 & @@ # &, Transpose@ {Values@ #, Keys@ #}] &@ PositionIndex@ Array[DivisorSigma[0, #] &, nn]] (* Michael De Vlieger, May 12 2017, Version 10 *)
  • PARI
    rgs_transform(invec) = { my(occurrences = Map(), outvec = vector(length(invec)), u=1); for(i=1, length(invec), if(mapisdefined(occurrences,invec[i]), my(pp = mapget(occurrences, invec[i])); outvec[i] = outvec[pp] , mapput(occurrences,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])); }
    A000005(n) = numdiv(n);
    write_to_bfile(1,rgs_transform(vector(10000,n,A000005(n))),"b286605.txt");

A286617 Restricted growth sequence of A278217 (prime-signature of A075159(1+n)).

Original entry on oeis.org

1, 2, 2, 3, 4, 2, 3, 5, 6, 4, 2, 4, 6, 3, 5, 7, 8, 6, 4, 9, 4, 2, 4, 6, 10, 6, 3, 6, 8, 5, 7, 11, 12, 8, 6, 13, 9, 4, 9, 13, 6, 4, 2, 4, 9, 4, 6, 8, 14, 10, 6, 13, 6, 3, 6, 10, 14, 8, 5, 8, 12, 7, 11, 15, 16, 12, 8, 17, 13, 6, 13, 18, 13, 9, 4, 9, 19, 9, 13, 17, 8, 6, 4, 9, 4, 2, 4, 6, 13, 9, 4, 9, 13, 6, 8, 12, 20, 14, 10, 18, 13, 6, 13, 18, 10, 6, 3, 6, 13
Offset: 0

Views

Author

Antti Karttunen, May 17 2017

Keywords

Crossrefs

Programs

  • PARI
    rgs_transform(invec) = { my(occurrences = Map(), outvec = vector(length(invec)), u=1); for(i=1, length(invec), if(mapisdefined(occurrences,invec[i]), my(pp = mapget(occurrences, invec[i])); outvec[i] = outvec[pp] , mapput(occurrences,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])); }
    A005811(n) = hammingweight(bitxor(n, n>>1));  \\ This function from Gheorghe Coserea, Sep 03 2015
    A286468(n) = { my(p=((n+1)%2), i=0, m=1); while(n>0, if(((n%2)==p), m *= prime(i), p = (n%2); i = i+1); n = n\2); m };
    A075157(n) = if(!n,n,(prime(A005811(n))*A286468(n))-1);
    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
    A278217(n) = A046523(1+A075157(n));
    write_to_bfile(0,rgs_transform(vector(65538,n,A278217(n-1))),"b286617.txt");

A286539 Restricted growth sequence of A286538.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, May 17 2017

Keywords

Crossrefs

A324390 Lexicographically earliest positive sequence such that a(i) = a(j) => A278219(i) = A278219(j) and A324386(i) = A324386(j), for all i, j >= 0.

Original entry on oeis.org

1, 2, 3, 2, 3, 4, 5, 2, 6, 7, 8, 4, 5, 9, 10, 2, 3, 7, 11, 7, 8, 12, 13, 4, 14, 15, 16, 9, 17, 18, 14, 2, 6, 7, 19, 20, 11, 21, 22, 7, 23, 24, 25, 26, 27, 28, 27, 4, 14, 29, 30, 15, 31, 32, 33, 9, 34, 35, 36, 9, 37, 38, 37, 2, 39, 40, 11, 7, 41, 42, 43, 40, 41, 44, 45, 46, 47, 48, 47, 7, 49, 50, 51, 24, 52, 53, 54, 55, 56, 57, 58, 42, 59, 60, 56, 4, 61, 62, 63
Offset: 0

Views

Author

Antti Karttunen, Feb 27 2019

Keywords

Comments

Restricted growth sequence transform of the ordered pair [A278219(n), A324386(n)].

Crossrefs

Cf. also A286619, A324343, A324344, A324380 (compare the scatter-plots).

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; };
    A005940(n) = { my(p=2, t=1); n--; until(!n\=2, if((n%2), (t*=p), p=nextprime(p+1))); t }; \\ From A005940
    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));
    A003188(n) = bitxor(n, n>>1);
    A278219(n) = A278222(A003188(n));
    Aux324390(n) = [A278219(n), A324386(n)]; \\ See code for A324386 in that entry.
    v324390 = rgs_transform(vector(1+up_to,n,Aux324390(n-1)));
    A324390(n) = v324390[1+n];

Formula

a(A000225(n)) = 2 for all n >= 1.

A286581 Restricted growth sequence transform of A286580.

Original entry on oeis.org

1, 2, 3, 2, 3, 4, 5, 2, 3, 6, 4, 5, 7, 6, 5, 2, 3, 6, 6, 4, 8, 9, 5, 7, 10, 6, 5, 11, 9, 6, 5, 2, 3, 6, 6, 6, 8, 12, 4, 8, 9, 9, 5, 13, 13, 10, 7, 10, 14, 6, 5, 12, 12, 11, 9, 10, 6, 5, 15, 14, 9, 6, 5, 2, 3, 6, 6, 6, 8, 12, 6, 8, 12, 12, 4, 13, 16, 9, 8, 9, 16, 9, 5, 13, 17, 13, 13, 10, 10, 7, 18, 19, 12, 14, 10, 14, 20, 6, 5, 18, 12, 12, 12, 10, 11, 9
Offset: 0

Views

Author

Antti Karttunen, Jun 03 2017

Keywords

Crossrefs

A352888 Lexicographically earliest infinite sequence such that a(i) = a(j) => A278219(A109812(i)) = A278219(A109812(j)), for all i, j >= 1.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Apr 07 2022

Keywords

Comments

Restricted growth sequence transform of A278219(A109812(n)).
For all i, j: a(i) = a(j) => A352889(i) = A352889(j).

Crossrefs

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; };
    v109812 = readvec("b109812_to10e5.txt"); \\ Prepared from b-file data with gawk ' { print $2 } '
    up_to = #v109812;
    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
    A003188(n) = bitxor(n, n>>1);
    A278219(n) = A046523(A005940(1+A003188(n)));
    A109812(n) = v109812[n];
    v352888 = rgs_transform(vector(up_to, n, A278219(A109812(n))));
    A352888(n) = v352888[n];

A366262 Lexicographically earliest infinite sequence such that a(i) = a(j) => A366261(i) = A366261(j) for all i, j >= 0.

Original entry on oeis.org

1, 2, 3, 2, 3, 2, 4, 5, 6, 2, 4, 7, 4, 5, 3, 7, 8, 2, 4, 7, 4, 7, 4, 9, 8, 10, 3, 7, 11, 7, 6, 5, 6, 2, 4, 7, 4, 7, 4, 9, 8, 12, 4, 9, 13, 9, 8, 7, 13, 12, 3, 7, 11, 7, 11, 7, 13, 14, 15, 5, 8, 14, 8, 10, 15, 2, 4, 7, 4, 7, 4, 9, 8, 12, 4, 9, 13, 9, 8, 7, 13, 16, 4, 9, 13, 9, 13, 9, 17, 16, 18, 7, 13, 19, 13, 12, 8, 10
Offset: 0

Views

Author

Antti Karttunen, Oct 05 2023

Keywords

Comments

Restricted growth sequence transform of A366261.
For all i, j >= 0: a(i) = a(j) => A366254(i) = A366254(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; };
    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]); };
    A209229(n) = (n && !bitand(n,n-1));
    A053644(n) = { my(k=1); while(k<=n, k<<=1); (k>>1); };
    A303767(n) = if(!n,n,if(A209229(n),n+A303767(n-1),A053644(n)+A303767(n-A053644(n)-1)));
    A366260(n) = A005940(1+A303767(n));
    A366261(n) = A046523(A366260(n));
    v366262 = rgs_transform(vector(1+up_to,n,A366261(n-1)));
    A366262(n) = v366262[1+n];

A304745 Restricted growth sequence transform of A046523(A207901(n)).

Original entry on oeis.org

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

Views

Author

Antti Karttunen, May 27 2018

Keywords

Comments

For all i, j: a(i) = a(j) => A005811(i) = A005811(j).

Crossrefs

Programs

  • PARI
    up_to_e = 17; \\ Good for computing up to n = (2^up_to_e)-1
    v050376 = vector(up_to_e);
    ispow2(n) = (n && !bitand(n,n-1));
    i = 0; for(n=1,oo,if(ispow2(isprimepower(n)), i++; v050376[i] = n); if(i == up_to_e,break));
    A050376(n) = v050376[n];
    A052330(n) = { my(p=1,i=1); while(n>0, if(n%2, p *= A050376(i)); i++; n >>= 1); (p); };
    A003188(n) = bitxor(n, n>>1);
    A207901(n) = A052330(A003188(n));
    A046523(n) = { my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]); };  \\ From A046523
    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; };
    v304745 = rgs_transform(vector(65538,n,A046523(A207901(n-1))));
    A304745(n) = v304745[1+n];

A324533 Lexicographically earliest positive sequence such that a(i) = a(j) => A002487(i) = A002487(j) and A278219(i) = A278219(j), for all i, j >= 0.

Original entry on oeis.org

1, 2, 3, 4, 3, 5, 6, 7, 3, 8, 9, 10, 6, 11, 12, 13, 3, 11, 14, 15, 9, 16, 17, 18, 6, 19, 17, 20, 12, 15, 21, 22, 3, 23, 24, 25, 14, 26, 27, 28, 9, 29, 30, 31, 17, 32, 33, 34, 6, 35, 27, 36, 17, 37, 38, 39, 12, 40, 33, 39, 21, 25, 41, 42, 3, 15, 43, 39, 24, 44, 45, 46, 14, 47, 48, 49, 27, 50, 51, 46, 9, 52, 48, 53, 30, 54, 55, 56, 17, 57, 58, 59, 33, 60, 61, 62, 6
Offset: 0

Views

Author

Antti Karttunen, Mar 05 2019

Keywords

Comments

Restricted growth sequence transform of the ordered pair [A002487(n), A278219(n)].

Crossrefs

Cf. also A323889 (compare the scatterplots).

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; };
    A002487(n) = { my(a=1, b=0); while(n>0, if(bitand(n, 1), b+=a, a+=b); n>>=1); (b); }; \\ From A002487
    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
    A003188(n) = bitxor(n, n>>1);
    A278219(n) = A046523(A005940(1+A003188(n)));
    Aux324533(n) = [A002487(n), A278219(n)];
    v324533 = rgs_transform(vector(1+up_to,n,Aux324533(n-1)));
    A324533(n) = v324533[1+n];

Formula

For n >= 1, a(2^n) = 3.
Previous Showing 11-19 of 19 results.