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.

A324886 a(n) = A276086(A108951(n)).

Original entry on oeis.org

2, 3, 5, 9, 7, 25, 11, 15, 35, 49, 13, 625, 17, 121, 117649, 225, 19, 1225, 23, 2401, 1771561, 169, 29, 875, 717409, 289, 55, 14641, 31, 184877, 37, 21, 4826809, 361, 36226650889, 1500625, 41, 529, 24137569, 77, 43, 143, 47, 28561, 1127357, 841, 53, 1715, 902613283, 514675673281, 47045881, 83521, 59, 3025, 8254129, 214358881, 148035889, 961, 61
Offset: 1

Views

Author

Antti Karttunen, Mar 30 2019

Keywords

Crossrefs

Programs

  • Mathematica
    With[{b = MixedRadix[Reverse@ Prime@ Range@ 120]}, Array[Function[k, Times @@ Power @@@ # &@ Transpose@ {Prime@ Range@ Length@ k, Reverse@ k}]@ IntegerDigits[Apply[Times, Map[#1^#2 & @@ # &, FactorInteger[#] /. {p_, e_} /; e > 0 :> {Times @@ Prime@ Range@ PrimePi@ p, e}]], b] &, 58]] (* Michael De Vlieger, Nov 18 2019 *)
    A276086[n0_] := Module[{m = 1, i = 1, n = n0, p}, While[n > 0, p = Prime[i]; m *= p^Mod[n, p]; n = Quotient[n, p]; i++]; m];
    (* b is A108951 *)
    b[n_] := b[n] = Module[{pe = FactorInteger[n], p, e}, If[Length[pe] > 1, Times @@ b /@ Power @@@ pe, {{p, e}} = pe; Times @@ (Prime[Range[ PrimePi[p]]]^e)]]; b[1] = 1;
    a[n_] := A276086[b[n]];
    Array[a, 100] (* Jean-François Alcover, Dec 01 2021, after _Antti Karttunen in A296086 *)
  • PARI
    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(i=0,m=1,pr=1,nextpr); while((n>0),i=i+1; nextpr = prime(i)*pr; if((n%nextpr),m*=(prime(i)^((n%nextpr)/pr));n-=(n%nextpr));pr=nextpr); m; };
    A324886(n) = A276086(A108951(n));

Formula

a(n) = A276086(A108951(n)).
a(n) = A117366(n) * A324896(n).
A001222(a(n)) = A324888(n).
A020639(a(n)) = A117366(n).
A032742(a(n)) = A324896(n).
a(A000040(n)) = A000040(1+n).
From Antti Karttunen, Jul 09 2021: (Start)
For n > 1, a(n) = A003961(A329044(n)).
a(n) = A346091(n) * A344592(n).
a(n) = A346106(n) / A346107(n).
A003415(a(n)) = A329047(n).
A003557(a(n)) = A344592(n).
A342001(a(n)) = A342920(n) = A329047(n) / A344592(n).
(End)