A086471 - OEIS

A086471

Product of distinct (smallest) prime signature divisors. In case of two or more divisors with the same prime signature the smallest is considered to evaluate the product.

1, 2, 3, 8, 5, 12, 7, 64, 27, 20, 11, 576, 13, 28, 45, 1024, 17, 1944, 19, 1600, 63, 44, 23, 110592, 125, 52, 729, 3136, 29, 360, 31, 32768, 99, 68, 175, 20736, 37, 76, 117, 512000, 41, 504, 43, 7744, 18225, 92, 47, 84934656, 343, 25000, 153, 10816, 53

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OFFSET

1,2

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

FORMULA

a(p) = p and a(p^r) = p^(T(r)) where p is a prime and T(r) = the r-th triangular number = r(r+1)/2.

MATHEMATICA

a[n_] := Module[{d = Rest[Divisors[n]]}, Times @@ DeleteDuplicatesBy[{#, Sort[FactorInteger[#][[;; , 2]]]} & /@ d, Last][[;; , 1]]]; Array[a, 60] (* Amiram Eldar, Jul 25 2024 *)

CROSSREFS

Cf. A086469.

Sequence in context: A344368 A342768 A340514 * A328846 A249154 A262351

Adjacent sequences: A086468 A086469 A086470 * A086472 A086473 A086474

KEYWORD

nonn

AUTHOR

Amarnath Murthy, Jul 21 2003

EXTENSIONS

More terms from David Wasserman, Mar 07 2005

STATUS

approved