1,3

Antti Karttunen, Table of n, a(n) for n = 1..10000

Index entries for sequences related to lcm's

Index entries for sequences computed from indices in prime factorization

a(1) = 1; for n > 1, a(n) = lcm(A055396(n), a(A028234(n)).

Other identities. For all n >= 1:

a(A007947(n)) = a(n).

a(A181819(n)) = A072411(n).

Here primepi (A000720) gives the index of its prime argument:

n = 14 = 2 * 7, thus a(14) = lcm(primepi(2), primepi(7)) = lcm(1,4) = 4.

n = 21 = 3 * 7, thus a(21) = lcm(primepi(3), primepi(7)) = lcm(2,4) = 4.

Table[Apply[LCM, PrimePi[FactorInteger[n][[All, 1]] ]] + Boole[n == 1], {n, 105}] (* Michael De Vlieger, Aug 14 2017 *)

(Scheme) (define (A290103 n) (if (= 1 n) n (lcm (A055396 n) (A290103 (A028234 n))))) ;; Antti Karttunen, Aug 13 2017

Cf. A000040, A000720, A003963, A007947, A156061, A290104, A290105.

Cf. also A072411, A181819.

Sequence in context: A108230 A253558 A061395 * A156061 A225395 A295877

Adjacent sequences: A290100 A290101 A290102 * A290104 A290105 A290106

nonn

Antti Karttunen, Aug 13 2017

approved