A064354 - OEIS

A064354

Distinct values arising in the sequence of the least common multiples of the first n composite numbers.

1, 4, 12, 24, 72, 360, 2520, 5040, 55440, 277200, 3603600, 10810800, 21621600, 367567200, 6983776800, 160626866400, 1124388064800, 32607253879200, 1010824870255200, 2021649740510400, 74801040398884800, 224403121196654400

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

OFFSET

1,2

LINKS

Harry J. Smith, Table of n, a(n) for n = 1..100

EXAMPLE

Different from A003418 and A051451.

MATHEMATICA

t=t=Select[ Range[ 1, 200 ], !PrimeQ[ # ] & ] Union[ Table[ Apply[ LCM, Table[ Part[ t, w ], {w, 1, s} ] ], {s, 1, 100} ] ]

Join[{1}, With[{cmps=Select[Range[100], CompositeQ]}, Table[LCM@@Take[cmps, n], {n, Length[cmps]}]]]//Union (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Dec 06 2018 *)

PROG

(PARI) { n=0; b=1; for (m=1, 10^9, if (m>1, if (isprime(m) || (b=lcm(a, m)) == a, next)); write("b064354.txt", n++, " ", a=b); if (n==100, break) ) } \\ Harry J. Smith, Sep 12 2009

CROSSREFS

Cf. A002808, A003418, A051451, A025543.

Sequence in context: A296358 A282512 A025543 * A199903 A218034 A140813

Adjacent sequences: A064351 A064352 A064353 * A064355 A064356 A064357

KEYWORD

nonn

AUTHOR

Labos Elemer, Sep 25 2001

EXTENSIONS

a(22) from Harry J. Smith, Sep 12 2009

Definition clarified by Harvey P. Dale, Dec 06 2018

STATUS

approved