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 1-3 of 3 results.

A324577 a(n) = A025487(n) * A324576(n) = A025487(n) * A276086(A025487(n)).

Original entry on oeis.org

2, 6, 36, 30, 120, 300, 3600, 15000, 210, 672, 1260, 42000, 2940, 28224, 88200, 164640, 288120, 4609920, 216090000, 21176820, 564715200, 2310, 11880, 18480, 4435200, 19404000, 66555720, 44370480000, 50820, 1306800, 2845920, 63748608, 5856903360, 328703760, 306790176000, 12298440, 7906140000, 645668100, 33746919360, 15874550866944
Offset: 1

Views

Author

Antti Karttunen, Mar 09 2019

Keywords

Comments

Note that A324198(A025487(n)) = gcd(A025487(n), A324576(n)) = 1 for all n, because each term of A025487 is a product of primorials.

Links

Crossrefs

Cf. A025487, A276086, A324198, A324576, A324579, A324580.
Cf. also A324582 (a subsequence).

Programs

  • PARI
    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; };
A324577(n) = A025487(n)*A276086(A025487(n));

Formula

a(n) = A025487(n) * A324576(n) = A025487(n) * A276086(A025487(n)).
a(n) = A324580(A025487(n)).

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

Links

Crossrefs

Cf. A034386, A108951, A117366, A276086, A324887, A324888, A324896, A329047, A342920, A344592, A346106, A346107.
Permutation of A324576.
Cf. also A346105.

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)

A324581 a(n) = A276086(A002182(n)).

Original entry on oeis.org

2, 3, 9, 5, 25, 625, 35, 875, 49, 2401, 117649, 77, 184877, 456533, 14641, 1771561, 214358881, 143, 20449, 2924207, 418161601, 8550986578849, 174859124550883201, 3575694237941010577249, 23298085122481, 1599034490244763, 32698656291015158587, 30466726698629, 39841104144361, 52099905419549, 89093921102069, 152355876914189, 260537564663909
Offset: 1

Views

Author

Antti Karttunen, Mar 09 2019

Keywords

Comments

Note that gcd(a(n), A002182(n)) = A324198(A002182(n)) = 1 for all n because each term of A002182 is a product of primorial numbers (A002110).

Links

Crossrefs

Subsequence of A324576.
Cf. A002110, A002182, A276086, A324198, A324381, A324382, A324582.

Programs

  • Mathematica
    Block[{b = MixedRadix[Reverse@ Prime@ Range@ 20], s = DivisorSigma[0, Range[10^5]], t}, t = Map[FirstPosition[s, #][[1]] &, Union@ FoldList[Max, s]]; Array[Times @@ Power @@@ # &@ Transpose@ {Prime@ Range@ Length@ #, Reverse@ #} &@ IntegerDigits[(*a002182[[#]]*)t[[#]], b] &, Length@ t]] (* Michael De Vlieger, Mar 18 2019 *)
  • PARI
    \\ A002182 assumed to be precomputed
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; };
A324581(n) = A276086(A002182(n));

Formula

a(n) = A276086(A002182(n)).
a(n) = A324582(n)/A002182(n).
A001221(a(n)) = A324381(n).
A001222(a(n)) = A324382(n).
Showing 1-3 of 3 results.

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