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 16 results. Next

A304748 Restricted growth sequence transform of A291759(n), formed from 2-digits in ternary representation of A048673(n).

Original entry on oeis.org

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

Views

Author

Antti Karttunen, May 29 2018

Keywords

Crossrefs

Cf. also A304746.

Programs

  • PARI
    A003961(n) = my(f = factor(n)); for (i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); \\ From A003961
    A048673(n) = (A003961(n)+1)/2;
    A289814(n) = { my (d=digits(n, 3)); fromdigits(vector(#d, i, if (d[i]==2, 1, 0)), 2); } \\ From A289814
    A291759(n) = A289814(A048673(n));
    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; };
    v304748 = rgs_transform(vector(65537,n,A291759(n)));
    A304748(n) = v304748[n];

A340382 Lexicographically earliest infinite sequence such that a(i) = a(j) => A278222(A291759(i)) = A278222(A291759(j)), for all i, j >= 1.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Jan 16 2021

Keywords

Crossrefs

Cf. A340377 (positions of ones).
Cf. also A305302.

Programs

  • PARI
    up_to = 65537;
    A003961(n) = my(f = factor(n)); for (i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); \\ From A003961
    A048673(n) = (A003961(n)+1)/2;
    A289814(n) = { my (d=digits(n, 3)); fromdigits(vector(#d, i, if (d[i]==2, 1, 0)), 2); } \\ From A289814
    A291759(n) = A289814(A048673(n));
    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));
    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; };
    v340382 = rgs_transform(vector(up_to,n,A278222(A291759(n))));
    A340382(n) = v340382[n];

A351032 a(n) = Product_{d|n, dA019565(A291759(d)).

Original entry on oeis.org

1, 1, 1, 2, 1, 2, 1, 4, 1, 2, 1, 24, 1, 6, 1, 8, 1, 12, 1, 8, 3, 6, 1, 480, 1, 2, 1, 72, 1, 120, 1, 16, 3, 2, 3, 480, 1, 2, 1, 32, 1, 216, 1, 120, 5, 6, 1, 13440, 3, 60, 1, 120, 1, 168, 3, 1440, 1, 6, 1, 144000, 1, 10, 3, 32, 1, 1080, 1, 8, 3, 72, 1, 26880, 1, 10, 75, 24, 9, 1080, 1, 128, 7, 10, 1, 86400, 1, 30, 3
Offset: 1

Views

Author

Antti Karttunen, Jan 29 2022

Keywords

Crossrefs

Cf. A019565, A048673, A289814, A291759, A351030, A351031, A351034 (rgs-transform).
Cf. also A293222.

Programs

  • PARI
    A019565(n) = { my(m=1, p=1); while(n>0, p = nextprime(1+p); if(n%2, m *= p); n >>= 1); (m); };
    A048673(n) = { my(f = factor(n)); for (i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); (1+factorback(f))/2; };
    A289814(n) = { my(d=digits(n, 3)); fromdigits(vector(#d, i, if (d[i]==2, 1, 0)), 2); } \\ From A289814
    A291759(n) = A289814(A048673(n));
    A351032(n) = { my(m=1); fordiv(n,d,if(dA019565(A291759(d)))); (m); };

A340383 Lexicographically earliest infinite sequence such that a(i) = a(j) => f(i) = f(j), where f(n) = [A278222(A304759(n)), A278222(A291759(n))], for all i, j >= 1.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Jan 16 2021

Keywords

Comments

Restricted growth sequence transform of the ordered pair [A340381(n), A340382(n)], or equally, of the function f(n) = A290093(A048673(n)).
For all i, j: a(i) = a(j) => A286586(i) = A286586(j) => A286585(i) = A286585(j).

Crossrefs

Programs

  • PARI
    up_to = 65537;
    A003961(n) = my(f = factor(n)); for (i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); \\ From A003961
    A048673(n) = (A003961(n)+1)/2;
    A289814(n) = { my (d=digits(n, 3)); fromdigits(vector(#d, i, if (d[i]==2, 1, 0)), 2); } \\ From A289814
    A291759(n) = A289814(A048673(n));
    A289813(n) = { my (d=digits(n, 3)); fromdigits(vector(#d, i, if (d[i]==1, 1, 0)), 2); } \\ From A289813
    A304759(n) = A289813(A048673(n));
    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));
    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; };
    Aux340383(n) = [A278222(A291759(n)),A278222(A304759(n))];
    v340383 = rgs_transform(vector(up_to,n,Aux340383(n)));
    A340383(n) = v340383[n];

A340684 Lexicographically earliest infinite sequence such that a(i) = a(j) => f(i) = f(j), where f(n) = [A291759(n), A278222(A304759(n))], for all i, j >= 1.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Jan 16 2021

Keywords

Comments

Restricted growth sequence transform of the ordered pair [A291759(n), A278222(A304759(n))].
For all i, j: a(i) = a(j) => A340383(i) = A340383(j).

Crossrefs

Programs

  • PARI
    up_to = 65537;
    A003961(n) = my(f = factor(n)); for (i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); \\ From A003961
    A048673(n) = (A003961(n)+1)/2;
    A289814(n) = { my (d=digits(n, 3)); fromdigits(vector(#d, i, if (d[i]==2, 1, 0)), 2); } \\ From A289814
    A291759(n) = A289814(A048673(n));
    A289813(n) = { my (d=digits(n, 3)); fromdigits(vector(#d, i, if (d[i]==1, 1, 0)), 2); } \\ From A289813
    A304759(n) = A289813(A048673(n));
    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));
    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; };
    Aux340684(n) = [A291759(n),A278222(A304759(n))];
    v340684 = rgs_transform(vector(up_to,n,Aux340684(n)));
    A340684(n) = v340684[n];

A304759 Binary encoding of 1-digits in ternary representation of A048673(n).

Original entry on oeis.org

1, 0, 2, 2, 3, 0, 0, 6, 7, 4, 1, 2, 4, 4, 0, 14, 5, 12, 6, 10, 9, 0, 4, 6, 1, 0, 4, 10, 5, 8, 1, 30, 8, 8, 14, 26, 2, 8, 13, 22, 3, 16, 0, 2, 17, 12, 8, 14, 1, 0, 10, 2, 10, 0, 9, 22, 3, 8, 11, 18, 9, 0, 18, 62, 0, 20, 12, 18, 1, 24, 13, 54, 15, 0, 28, 18, 0, 24, 12, 46, 37, 4, 8, 34, 7, 4, 0, 6, 11, 32, 23, 26, 22, 0
Offset: 1

Views

Author

Antti Karttunen, May 30 2018

Keywords

Comments

Compare the logarithmic scatterplot to those of A291759, A292250 and A304760.

Crossrefs

Cf. A048673, A289813, A304758 (rgs-transform), A340381.
Cf. A340376 (positions of zeros), A340378 (binary weight).

Programs

Formula

a(n) = A289813(A048673(n)).

A291760 Binary encoding of 2-digits in ternary representation of A254103(n).

Original entry on oeis.org

0, 0, 1, 0, 1, 0, 3, 2, 1, 0, 1, 2, 5, 0, 3, 0, 1, 4, 7, 2, 1, 4, 5, 0, 9, 0, 1, 4, 5, 0, 1, 2, 1, 8, 9, 2, 13, 0, 3, 6, 1, 4, 7, 0, 9, 0, 3, 4, 17, 4, 7, 8, 1, 8, 11, 2, 9, 12, 15, 2, 1, 4, 5, 6, 1, 20, 23, 2, 17, 4, 5, 6, 25, 0, 1, 10, 5, 8, 11, 0, 1, 8, 9, 12, 13, 0, 1, 2, 17, 0, 1, 4, 5, 8, 9, 0, 33, 8, 9, 12, 13, 16, 17, 0, 1, 16, 17, 2, 21, 0, 3, 6, 17
Offset: 0

Views

Author

Antti Karttunen, Sep 12 2017

Keywords

Crossrefs

Formula

a(n) = A289814(A254103(n)).

A291763 Binary encoding of 2-digits in ternary representation of A245612(n).

Original entry on oeis.org

0, 1, 1, 0, 1, 0, 3, 0, 1, 8, 1, 6, 5, 4, 1, 2, 1, 10, 23, 16, 1, 2, 13, 10, 9, 2, 7, 0, 1, 0, 3, 2, 1, 70, 21, 24, 45, 4, 33, 52, 1, 36, 3, 20, 25, 10, 21, 0, 17, 18, 5, 0, 13, 16, 3, 12, 1, 8, 1, 4, 5, 2, 5, 0, 1, 32, 139, 74, 41, 208, 49, 0, 89, 108, 11, 130, 65, 18, 103, 4, 1, 8, 73, 4, 5, 112, 41, 16, 49, 72, 19, 38, 41, 20, 1, 8, 33, 0, 35, 86, 9, 38
Offset: 0

Views

Author

Antti Karttunen, Sep 12 2017

Keywords

Crossrefs

Formula

a(n) = A289814(A245612(n)).

A292252 Number of trailing 2-digits in ternary representation of A048673(n).

Original entry on oeis.org

0, 1, 0, 1, 0, 2, 0, 1, 0, 1, 0, 1, 0, 2, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 3, 0, 1, 0, 3, 0, 1, 0, 1, 0, 1, 0, 2, 0, 1, 0, 1, 0, 1, 0, 2, 0, 1, 0, 1, 0, 1, 0, 3, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 2, 0, 1, 0, 2, 0, 1, 0, 2, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 2, 0, 1, 0, 1, 0, 1, 0, 4, 0, 1, 0, 1, 0, 1, 0, 2, 0, 1, 0, 2, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1
Offset: 1

Views

Author

Antti Karttunen, Sep 12 2017

Keywords

Crossrefs

Cf. A007814, A007949, A048673, A291759, A292251 (even bisection subtracted by one).
Cf. also A292242, A292262.

Programs

  • Mathematica
    If[First@ # == 2, Length@ #, 0] &@ Last@ Split@ IntegerDigits[#, 3] & /@ Table[(Times @@ Power[If[# == 1, 1, NextPrime@ #] & /@ First@ #, Last@ #] + 1)/2 &@ Transpose@ FactorInteger@ n, {n, 120}] (* Michael De Vlieger, Sep 12 2017 *)
  • Scheme
    (define (A292252 n) (A007949 (+ 1 (A048673 n))))
    (define (A292252 n) (A007814 (+ 1 (A291759 n))))
    (define (A292252 n) (if (odd? n) 0 (+ 1 (A292251 (/ n 2)))))

Formula

a(n) = A007949(1+A048673(n)).
a(n) = A007814(1+A291759(n)).
a(2n) = 1 + A292251(n/2), a(2n+1) = 0.

A292246 Base-2 expansion of a(n) encodes the steps where numbers of the form 3k+2 are encountered when map x -> A253889(x) is iterated down to 1, starting from x=n.

Original entry on oeis.org

0, 1, 0, 2, 3, 0, 4, 1, 2, 14, 5, 12, 6, 7, 8, 2, 1, 0, 0, 9, 26, 22, 3, 20, 6, 5, 16, 10, 29, 10, 4, 11, 30, 2, 25, 60, 56, 13, 28, 54, 15, 48, 24, 17, 44, 8, 5, 12, 38, 3, 30, 26, 1, 24, 20, 1, 18, 6, 19, 62, 14, 53, 4, 14, 45, 0, 42, 7, 124, 118, 41, 50, 58, 13, 116, 106, 11, 40, 104, 33, 32, 98, 21, 92, 6, 59, 88, 18, 21, 82, 76, 9, 34, 36, 23, 74
Offset: 1

Views

Author

Antti Karttunen, Sep 15 2017

Keywords

Examples

			For n = 2, the starting value is of the form 3k+2, after which follows A253889(3) = 1, the end point of iteration, which is not, thus a(2) = 1*(2^0) = 1.
For n = 4, the starting value is not of the form 3k+2, while A253889(4) = 2 is, thus a(4) = 0*(2^0) + 1*(2^1) = 2.
		

Crossrefs

Programs

  • Mathematica
    f[n_] := Times @@ Power[If[# == 1, 1, NextPrime[#, -1]] & /@ First@ #, Last@ #] &@ Transpose@ FactorInteger[2 n - 1]; g[n_] := (Times @@ Power[If[# == 1, 1, NextPrime@ #] & /@ First@ #, Last@ #] + 1)/2 &@ Transpose@ FactorInteger@ n; Map[FromDigits[#, 2] &[IntegerDigits[#, 3] /. d_ /; d > 0 :> d - 1] &, Array[a, 96]] (* Michael De Vlieger, Sep 16 2017 *)

Formula

a(1) = 0; for n > 1, a(n) = 2*a(A253889(n)) + floor((n mod 3)/2).
a(n) = A289814(A292243(n)).
A000120(a(n)) = A254045(n).
a(n) AND A292244(n) = a(n) AND A292245(n) = 0, where AND is a bitwise-AND (A004198).
Showing 1-10 of 16 results. Next