A236563 - OEIS

A236563

a(p^n)=p^(n+1)(p-1) if p is prime and a(nm)=lcm(a(n),a(m)) if gcd(n,m)=1.

1, 4, 18, 8, 100, 36, 294, 16, 54, 100, 1210, 72, 2028, 588, 900, 32, 4624, 108, 6498, 200, 882, 2420, 11638, 144, 500, 2028, 162, 1176, 23548, 900, 28830, 64, 10890, 4624, 14700, 216, 49284, 12996, 6084, 400, 67240, 1764, 77658, 4840, 2700, 23276, 101614

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

MATHEMATICA

fa=FactorInteger; lam[p_, s_] := p^(s + 1)(p - 1); lam[1] = 1; lam[n_] := {aux = 1; Do[aux = LCM[aux, lam[fa[n][[i, 1]], fa[n][[i, 2]]]], {i, 1, Length[fa[n]]}]; aux}[[1]]; Array[lam, 100]

PROG

(Haskell)

a236563 n = foldl lcm 1 $ zipWith (\p e -> p ^ (e + 1) * (p - 1))

(a027748_row n) (a124010_row n)

-- Reinhard Zumkeller, Feb 27 2014

CROSSREFS

Cf. A027748, A124010.

Sequence in context: A158320 A342153 A341800 * A264207 A264003 A077109

Adjacent sequences: A236560 A236561 A236562 * A236564 A236565 A236566

KEYWORD

nonn

AUTHOR

José María Grau Ribas, Feb 22 2014

STATUS

approved