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.

A352028 a(n) = Product p_{n*i}^e_i if the prime factorization of n is Product p_i^e_i.

Original entry on oeis.org

1, 3, 13, 49, 47, 481, 107, 6859, 3721, 3277, 257, 121841, 397, 11309, 22261, 7890481, 653, 1390861, 881, 1416521, 78373, 47479, 1279, 157208087, 143641, 92011, 15813251, 7018237, 1889, 14701639, 2293, 38579489651, 309709, 207527, 461939, 2938615681, 3119
Offset: 1

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Author

Alois P. Heinz, Mar 01 2022

Keywords

Comments

Or replace prime(i) in n by prime(n*i).
All terms are odd.

Examples

			a(1) = 1 because 1 is the empty product.
a(2) = 3 = prime(2) = prime(2*1) because 2 = prime(1).
a(3) = 13 = prime(6) = prime(3*2) because 3 = prime(2).
a(4) = 49 = 7^2 = prime(4)^2 = prime(4*1)^2 because 4 = prime(1)^2.
		

Crossrefs

Main diagonal of A352001.

Programs

  • Maple
    a:= n-> mul(ithprime(n*numtheory[pi](i[1]))^i[2], i=ifactors(n)[2]):
    seq(a(n), n=1..45);
  • PARI
    a(n) = my(f=factor(n)); for (k=1, #f~, f[k,1] = prime(n*primepi(f[k,1]))); factorback(f); \\ Michel Marcus, Mar 02 2022

Formula

a(n) = A352001(n,n).
a(prime(n)) = A228529(n) = A000040(A033286(n)).