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.

A323173 Sum of divisors computed for conjugated prime factorization: a(n) = A000203(A122111(n)).

Original entry on oeis.org

1, 3, 7, 4, 15, 12, 31, 6, 13, 28, 63, 18, 127, 60, 39, 8, 255, 24, 511, 42, 91, 124, 1023, 24, 40, 252, 31, 90, 2047, 72, 4095, 12, 195, 508, 120, 32, 8191, 1020, 403, 56, 16383, 168, 32767, 186, 93, 2044, 65535, 36, 121, 78, 819, 378, 131071, 48, 280, 120, 1651, 4092, 262143, 96, 524287, 8188, 217, 14, 600, 360, 1048575, 762, 3315, 234
Offset: 1

Views

Author

Antti Karttunen, Jan 10 2019

Keywords

Crossrefs

Programs

  • Mathematica
    A122111[n_] := Product[Prime[Sum[If[j < i, 0, 1], {j, #}]], {i, Max[#]}]&[ Flatten[Table[Table[PrimePi[f[[1]]], {f[[2]]}], {f, FactorInteger[n]}]]];
    a[n_] := With[{k = A122111[n]}, DivisorSigma[1, k]];
    Array[a, 70] (* Jean-François Alcover, Sep 23 2020 *)
  • 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)));
    A323173(n) = sigma(A122111(n));

Formula

a(n) = A000203(A122111(n)).
a(n) = 2*A122111(n) - A323174(n).
a(n) = A322819(n) * A038712(A122111(n)).

A322865 a(n) = A000265(A122111(n)).

Original entry on oeis.org

1, 1, 1, 3, 1, 3, 1, 5, 9, 3, 1, 5, 1, 3, 9, 7, 1, 15, 1, 5, 9, 3, 1, 7, 27, 3, 25, 5, 1, 15, 1, 11, 9, 3, 27, 21, 1, 3, 9, 7, 1, 15, 1, 5, 25, 3, 1, 11, 81, 45, 9, 5, 1, 35, 27, 7, 9, 3, 1, 21, 1, 3, 25, 13, 27, 15, 1, 5, 9, 45, 1, 33, 1, 3, 75, 5, 81, 15, 1, 11, 49, 3, 1, 21, 27, 3, 9, 7, 1, 35, 81, 5, 9, 3, 27, 13, 1, 135, 25, 63, 1, 15, 1, 7, 75
Offset: 1

Views

Author

Antti Karttunen, Dec 30 2018

Keywords

Crossrefs

Programs

  • Mathematica
    Array[#/2^IntegerExponent[#, 2] &@ 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
    A000265(n) = (n>>valuation(n, 2));
    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)));
    A322865(n) = A000265(A122111(n));

Formula

a(n) = A000265(A122111(n)).
a(n) = A122111(A322820(n)).
A000005(a(n)) = A322813(n).
A000203(a(n)) = A322819(n).
A122111(a(n)) = A322820(n).
A000120(a(n)) = A322867(n).

A322813 a(n) = A001227(A122111(n)).

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Dec 27 2018

Keywords

Crossrefs

Programs

Formula

a(n) = A001227(A122111(n)).

A324118 Sum of odd divisors in A156552(n): a(1) = 0, for n > 1, a(n) = A000593(A156552(n)) = A000203(A322993(n)).

Original entry on oeis.org

0, 1, 1, 4, 1, 6, 1, 8, 4, 13, 1, 12, 1, 18, 6, 24, 1, 14, 1, 20, 13, 48, 1, 24, 4, 84, 8, 48, 1, 32, 1, 32, 18, 176, 6, 40, 1, 258, 48, 56, 1, 38, 1, 68, 12, 800, 1, 48, 4, 31, 84, 132, 1, 30, 13, 72, 176, 1302, 1, 44, 1, 2736, 20, 104, 18, 96, 1, 304, 258, 42, 1, 72, 1, 4356, 14, 624, 6, 160, 1, 80, 24, 10928, 1, 124, 48, 20520, 800, 240, 1, 78, 13
Offset: 1

Views

Author

Antti Karttunen, Feb 20 2019

Keywords

Crossrefs

Programs

Formula

a(1) = 0; for n > 1, a(n) = A000593(A156552(n)) = A000203(A322993(n)) = A323243(2*A246277(n)).

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).

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; };
    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];

A322820 a(n) = A052126(n) * A006530(A052126(n)).

Original entry on oeis.org

1, 1, 1, 4, 1, 4, 1, 8, 9, 4, 1, 8, 1, 4, 9, 16, 1, 18, 1, 8, 9, 4, 1, 16, 25, 4, 27, 8, 1, 18, 1, 32, 9, 4, 25, 36, 1, 4, 9, 16, 1, 18, 1, 8, 27, 4, 1, 32, 49, 50, 9, 8, 1, 54, 25, 16, 9, 4, 1, 36, 1, 4, 27, 64, 25, 18, 1, 8, 9, 50, 1, 72, 1, 4, 75, 8, 49, 18, 1, 32, 81, 4, 1, 36, 25, 4, 9, 16, 1, 54, 49, 8, 9, 4, 25, 64, 1, 98, 27, 100, 1, 18, 1, 16, 75
Offset: 1

Views

Author

Antti Karttunen, Dec 27 2018

Keywords

Crossrefs

Cf. A000265, A006530, A052126, A070003 (positions where a(n) = n for n > 1), A122111, A319988, A322813, A322819, A322826 (restricted growth sequence transform).

Programs

Formula

a(n) = A052126(n) * A006530(A052126(n)).
a(n) = A122111(A000265(A122111(n))).
A052126(a(n)) = A052126(n).
a(n) <= n.
For all n > 1, A010051(n) + A319988(a(n)) = 1.

A336315 The number of divisors in the conjugated prime factorization of n: a(n) = A000005(A122111(n)).

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Jul 18 2020

Keywords

Crossrefs

Programs

  • PARI
    A336315(n) = if(1==n,n,my(p=apply(primepi,factor(n)[,1]~),m=1+p[1]); for(i=2, #p, m *= (1+p[i]-p[i-1])); (m));

Formula

a(n) = A000005(A122111(n)).
a(n) = A336316(n) + A034444(n).

A337204 Sum of the odd divisors of the primorial inflation of n.

Original entry on oeis.org

1, 1, 4, 1, 24, 4, 192, 1, 13, 24, 2304, 4, 32256, 192, 78, 1, 580608, 13, 11612160, 24, 624, 2304, 278691840, 4, 403, 32256, 40, 192, 8360755200, 78, 267544166400, 1, 7488, 580608, 3224, 13, 10166678323200, 11612160, 104832, 24, 427000489574400, 624, 18788021541273600, 2304, 240, 278691840, 901825033981132800, 4, 22971, 403
Offset: 1

Views

Author

Antti Karttunen, Aug 22 2020

Keywords

Crossrefs

Row 1 of A337205.
Cf. also A322819.

Programs

  • Mathematica
    Array[DivisorSum[Apply[Times, FactorInteger[#] /. {p_, e_} /; e > 0 :> Apply[Times, Prime@ Range@ PrimePi@ p]^e], # &, OddQ] &, 50] (* Michael De Vlieger, Aug 27 2020 *)
  • PARI
    A000593(n) = sigma(n>>valuation(n, 2));
    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
    A337204(n) = A000593(A108951(n));

Formula

a(n) = A000593(A108951(n)).
Showing 1-8 of 8 results.