A110957 (Sum{k=1..n} 1/c(k))*(product{j=1..n} c(j)), where c(j) is j-th composite.

1, 10, 104, 1128, 13008, 173376, 2634624, 42422400, 722304000, 13698201600, 286505164800, 6267431116800, 143150760345600, 3551498315366400, 91568579493888000, 2450311107084288000, 67966128937598976000

Offset

1,2

Links

Table of n, a(n) for n=1..17.

Example

Since the first 3 composites are 4, 6 and 8, the third term of the sequence is (1/4 +1/6 +1/8) *4 *6 *8 = 48 +32 +24 = 104.

Maple

c:=proc(n) if isprime(n)=false then n else fi end: C:=[seq(c(n), n=2..35)]: a:=n->sum(1/C[k], k=1..n)*product(C[j], j=1..n): seq(a(n), n=1..20); # Emeric Deutsch, Oct 06 2005

Crossrefs

Cf. A002808, A024451.

Sequence in context: A190954 A163309 A163165 * A077671 A117833 A117832

Adjacent sequences: A110954 A110955 A110956 * A110958 A110959 A110960

Keyword

nonn

Author

Leroy Quet, Sep 26 2005

Extensions

More terms from Emeric Deutsch, Oct 06 2005

Status

approved