A250033 a(n) gives the denominators for A250031(n) as well as for A250032(n).

1, 2, 2, 24, 15, 45, 35, 280, 630, 2100, 2310, 27720, 10010, 140140, 150150, 480480, 255255, 2297295, 4849845, 96996900, 101846745, 106696590, 111546435, 669278610, 929553625, 966735770, 1003917915, 3123300180, 3234846615, 48522699225, 100280245065, 1604483921040, 6618496174290, 6819056664420, 7019617154550, 7220177644680

Offset

1,2

Comments

See the comments in sequences A250031 and A250032.

Links

Stanislav Sykora, Table of n, a(n) for n = 1..1000

S. Sykora, On some number densities related to coprimes, Stan's Library, Vol.V, Nov 2014, DOI: 10.3247/SL5Math14.005

Formula

a(n)=A250031(n)+A250032(n).

Prog

(PARI) s_aux(n, p0, inp)={my(t=0/1, tt=0/1, in=inp, pp); while(1, pp=p0*prime(in); tt=n\pp; if(tt==0, break, t+=tt/pp-s_aux(n, pp, in++))); return(t)};
s(n)=1+s_aux(n, 1, 1);
a=vector(1000, n, denominator(s(n-1)/n))

Crossrefs

Cf. A250031, A250032.

Sequence in context: A048648 A229334 A120065 * A224479 A279311 A248812

Adjacent sequences: A250030 A250031 A250032 * A250034 A250035 A250036

Keyword

nonn,frac

Author

Stanislav Sykora, Nov 16 2014

Status

approved