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 1-8 of 8 results.

A334107 a(n) = A329697(A122111(n)).

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Apr 29 2020

Keywords

Crossrefs

Programs

  • Mathematica
    Map[Length@ NestWhileList[# - #/FactorInteger[#][[-1, 1]] &, #, # != 2^IntegerExponent[#, 2] &] - 1 &, Array[Times @@ Table[Prime[LengthWhile[#1, # >= j &] /. 0 -> 1], {j, #2}] & @@ {#, Max[#]} &@ PrimePi@ Flatten[ConstantArray[#1, {#2}] & @@@ FactorInteger@ #] &, 105] ] (* Michael De Vlieger, May 14 2020, after Robert G. Wilson v at A329697 *)
  • PARI
    A064989(n) = {my(f); f = factor(n); if((n>1 && f[1,1]==2), f[1,2] = 0); for (i=1, #f~, f[i,1] = precprime(f[i,1]-1)); factorback(f)};
    A122111(n) = if(1==n,n,prime(bigomega(n))*A122111(A064989(n)));
    A329697(n) = if(!bitand(n,n-1),0,1+A329697(n-(n/vecmax(factor(n)[, 1]))));
    A334107(n) = A329697(A122111(n));

Formula

a(n) = A329697(A122111(n)) = A329697(A322865(n)).
a(n) = A329697(A105560(n)) + a(A064989(n)).
For n >= 1, a(A001248(n)) = n, and these seem to be also the first occurrences of each n.

A322867 a(n) = A000120(A122111(n)).

Original entry on oeis.org

1, 1, 1, 2, 1, 2, 1, 2, 2, 2, 1, 2, 1, 2, 2, 3, 1, 4, 1, 2, 2, 2, 1, 3, 4, 2, 3, 2, 1, 4, 1, 3, 2, 2, 4, 3, 1, 2, 2, 3, 1, 4, 1, 2, 3, 2, 1, 3, 3, 4, 2, 2, 1, 3, 4, 3, 2, 2, 1, 3, 1, 2, 3, 3, 4, 4, 1, 2, 2, 4, 1, 2, 1, 2, 4, 2, 3, 4, 1, 3, 3, 2, 1, 3, 4, 2, 2, 3, 1, 3, 3, 2, 2, 2, 4, 3, 1, 4, 3, 6, 1, 4, 1, 3, 4
Offset: 1

Views

Author

Antti Karttunen, Dec 30 2018

Keywords

Crossrefs

Programs

  • Mathematica
    Array[DigitCount[#, 2, 1] &@ If[# < 3, 1, Block[{k = #, m = 0}, Times @@ Power @@@ Table[k -= m; k = DeleteCases[k, 0]; {Prime@Length@k, m = Min@ k}, Length@ Union@ k]] &@ Catenate[ConstantArray[PrimePi[#1], #2] & @@@ FactorInteger@ #]] &, 105] (* Michael De Vlieger, Dec 31 2018, after JungHwan Min at A122111 *)
  • PARI
    A064989(n) = {my(f); f = factor(n); if((n>1 && f[1,1]==2), f[1,2] = 0); for (i=1, #f~, f[i,1] = precprime(f[i,1]-1)); factorback(f)};
    A122111(n) = if(1==n,n,prime(bigomega(n))*A122111(A064989(n)));
    A322867(n) = hammingweight(A122111(n));

Formula

a(n) = A000120(A122111(n)) = A000120(A322865(n)) = A001222(A322863(n)).

A323903 a(n) = A002487(A122111(n)).

Original entry on oeis.org

1, 1, 1, 2, 1, 2, 1, 3, 4, 2, 1, 3, 1, 2, 4, 3, 1, 4, 1, 3, 4, 2, 1, 3, 8, 2, 7, 3, 1, 4, 1, 5, 4, 2, 8, 8, 1, 2, 4, 3, 1, 4, 1, 3, 7, 2, 1, 5, 14, 12, 4, 3, 1, 9, 8, 3, 4, 2, 1, 8, 1, 2, 7, 5, 8, 4, 1, 3, 4, 12, 1, 6, 1, 2, 18, 3, 14, 4, 1, 5, 9, 2, 1, 8, 8, 2, 4, 3, 1, 9, 14, 3, 4, 2, 8, 5, 1, 16, 7, 6, 1, 4, 1, 3, 18
Offset: 1

Views

Author

Antti Karttunen, Feb 09 2019

Keywords

Crossrefs

Programs

  • PARI
    A002487(n) = { my(a=1, b=0); while(n>0, if(bitand(n, 1), b+=a, a+=b); n>>=1); (b); }; \\ From A002487
    A064989(n) = {my(f); f = factor(n); if((n>1 && f[1,1]==2), f[1,2] = 0); for (i=1, #f~, f[i,1] = precprime(f[i,1]-1)); factorback(f)};
    A122111(n) = if(1==n,n,prime(bigomega(n))*A122111(A064989(n)));
    A323903(n) = A002487(A122111(n));

Formula

a(n) = A002487(A122111(n)) = A002487(A322865(n)).
a(p) = 1 for all primes p.

A334108 a(n) = A331410(A122111(n)).

Original entry on oeis.org

0, 0, 0, 1, 0, 1, 0, 2, 2, 1, 0, 2, 0, 1, 2, 1, 0, 3, 0, 2, 2, 1, 0, 1, 3, 1, 4, 2, 0, 3, 0, 2, 2, 1, 3, 2, 0, 1, 2, 1, 0, 3, 0, 2, 4, 1, 0, 2, 4, 4, 2, 2, 0, 3, 3, 1, 2, 1, 0, 2, 0, 1, 4, 2, 3, 3, 0, 2, 2, 4, 0, 3, 0, 1, 5, 2, 4, 3, 0, 2, 2, 1, 0, 2, 3, 1, 2, 1, 0, 3, 4, 2, 2, 1, 3, 2, 0, 5, 4, 3, 0, 3, 0, 1, 5
Offset: 1

Views

Author

Antti Karttunen, Apr 29 2020

Keywords

Crossrefs

Cf. A008578 (positions of zeros), A064989, A105560, A122111, A322865, A331410, A334107.

Programs

Formula

a(n) = A331410(A122111(n)) = A331410(A322865(n)).
a(n) = A331410(A105560(n)) + a(A064989(n)).

A331731 Odd part of A331595(n), where A331595(n) = gcd(A122111(n), A241909(n)).

Original entry on oeis.org

1, 1, 1, 3, 1, 3, 1, 5, 3, 3, 1, 5, 1, 3, 9, 7, 1, 15, 1, 5, 9, 3, 1, 7, 3, 3, 5, 5, 1, 15, 1, 11, 9, 3, 9, 7, 1, 3, 9, 7, 1, 15, 1, 5, 25, 3, 1, 11, 3, 45, 9, 5, 1, 7, 27, 7, 9, 3, 1, 7, 1, 3, 25, 13, 27, 15, 1, 5, 9, 45, 1, 11, 1, 3, 15, 5, 9, 15, 1, 11, 7, 3, 1, 7, 27, 3, 9, 7, 1, 7, 27, 5, 9, 3, 27, 13, 1, 135, 25, 7, 1, 15, 1, 7, 75
Offset: 1

Views

Author

Antti Karttunen, Jan 25 2020

Keywords

Crossrefs

Programs

Formula

a(n) = A000265(A331595(n)).

A322866 Lexicographically earliest such sequence a that a(i) = a(j) => A046523(A322863(i)) = A046523(A322863(j)) for all i, j.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Dec 30 2018

Keywords

Comments

Restricted growth sequence transform of A046523(A322863(n)).
Equally, restricted growth sequence transform of A278222(A322865(n)).
For all i, j: a(i) = a(j) => A322867(i) = A322867(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; };
    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
    A064989(n) = {my(f); f = factor(n); if((n>1 && f[1,1]==2), f[1,2] = 0); for (i=1, #f~, f[i,1] = precprime(f[i,1]-1)); factorback(f)};
    A122111(n) = if(1==n,n,prime(bigomega(n))*A122111(A064989(n)));
    A322863(n) = if(!n,1,A005940(1+A122111(n)));
    v322866 = rgs_transform(vector(up_to,n,A046523(A322863(n))));
    A322866(n) = v322866[n];

A331286 Odd part of number of divisors of primorial inflation of n: a(n) = A000265(A329605(n)).

Original entry on oeis.org

1, 1, 1, 3, 1, 3, 1, 1, 9, 3, 1, 1, 1, 3, 9, 5, 1, 3, 1, 1, 9, 3, 1, 5, 27, 3, 1, 1, 1, 3, 1, 3, 9, 3, 27, 15, 1, 3, 9, 5, 1, 3, 1, 1, 1, 3, 1, 3, 81, 9, 9, 1, 1, 5, 27, 5, 9, 3, 1, 15, 1, 3, 1, 7, 27, 3, 1, 1, 9, 9, 1, 9, 1, 3, 3, 1, 81, 3, 1, 3, 25, 3, 1, 15, 27, 3, 9, 5, 1, 5, 81, 1, 9, 3, 27, 7, 1, 27, 1, 45, 1, 3, 1, 5, 3
Offset: 1

Views

Author

Antti Karttunen, Jan 14 2020

Keywords

Crossrefs

Programs

  • PARI
    A331286(n) = if(1==n,1,my(f=factor(n),e=1,m=1); forstep(i=#f~,1,-1, e += f[i,2]; m *= (e>>valuation(e,2))^(primepi(f[i,1])-if(1==i,0,primepi(f[i-1,1])))); (m));

Formula

a(n) = A000265(A329605(n)).
a(n) = A212181(A108951(n)).

A331732 Odd part of A241909(n).

Original entry on oeis.org

1, 1, 1, 3, 1, 9, 1, 5, 3, 27, 1, 25, 1, 81, 9, 7, 1, 15, 1, 125, 27, 243, 1, 49, 3, 729, 5, 625, 1, 75, 1, 11, 81, 2187, 9, 35, 1, 6561, 243, 343, 1, 375, 1, 3125, 25, 19683, 1, 121, 3, 45, 729, 15625, 1, 21, 27, 2401, 2187, 59049, 1, 245, 1, 177147, 125, 13, 81, 1875, 1, 78125, 6561, 225, 1, 77, 1, 531441, 15, 390625, 9, 9375, 1, 1331
Offset: 1

Views

Author

Antti Karttunen, Jan 25 2020

Keywords

Crossrefs

Programs

  • PARI
    A000265(n) = (n/2^valuation(n, 2));
    A241909(n) = if(1==n||isprime(n),2^primepi(n),my(f=factor(n),h=1,i,m=1,p=1,k=1); while(k<=#f~, p = nextprime(1+p); i = primepi(f[k,1]); m *= p^(i-h); h = i; if(f[k,2]>1, f[k,2]--, k++)); (p*m));
    A331732(n) = A000265(A241909(n));

Formula

a(n) = A000265(A241909(n)).
Showing 1-8 of 8 results.