A068510 a(n) = lcm(1,...,n) - (product of primes <= n).

0, 0, 0, 6, 30, 30, 210, 630, 2310, 2310, 25410, 25410, 330330, 330330, 330330, 690690, 11741730, 11741730, 223092870, 223092870, 223092870, 223092870, 5131136010, 5131136010, 26548051530, 26548051530, 80090340330, 80090340330

Offset

1,4

References

Tenenbaum, G. (2015). Introduction to analytic and probabilistic number theory, 3rd ed., American Mathematical Soc. See page 22.

Links

T. D. Noe, Table of n, a(n) for n = 1..200

Maple

a[1] := 0:a[2] := 0:l := 2:p := 3:pp := 2:for i from 3 to 50 do l := ilcm(l, i): if(p=i) then pp := pp*p:p := nextprime(p):end if: a[i] := l-pp:end do:q := seq(a[j], j=1..50);

Mathematica

f[n_] := (LCM @@ Table[i, {i, n}] - Product[Prime[i], {i, PrimePi[n]}]); Table[f[n], {n, 30}]

Crossrefs

Cf. A059794, A068511.

Sequence in context: A287733 A066197 A078638 * A147798 A351226 A351228

Adjacent sequences: A068507 A068508 A068509 * A068511 A068512 A068513

Keyword

nonn,easy

Author

N. J. A. Sloane, Mar 21 2002

Extensions

More terms from Sascha Kurz, Mar 23 2002

Status

approved