A241191 Numerator of Sum_{i=1..n} 1/(prime(i)*prime(i+1)*prime(i+2)).

1, 3, 1, 93, 145, 213, 289, 365, 260511, 9645025, 395623447, 17017308303, 800016993275, 902324346127, 2502504187659113, 152669617912106167, 10229758110750827711, 726365554791051924279, 53027901964339123037045, 57389311757677767147397

Offset

1,2

Links

Robert Israel, Table of n, a(n) for n = 1..361

Example

1/30, 3/70, 1/22, 93/2002, 145/3094, 213/4522, 289/6118, 365/7714, 260511/5500082, 9645025/203503034, 395623447/8343624394, 17017308303/358775848942, 800016993275/16862464900274, 902324346127/19015119993926, ...

Maple

g:= n-> add(1/(ithprime(i)*ithprime(i+1)*ithprime(i+2)), i=1..n);
t1:=[seq(g(n), n=1..20)];
t1a:=map(numer, t1); # A241191
t1b:=map(denom, t1); # A241192

Crossrefs

Cf. A024451/A002110, A241189/A241190, A241191/A241192.

Sequence in context: A370331 A370431 A331778 * A352232 A221195 A071291

Adjacent sequences: A241188 A241189 A241190 * A241192 A241193 A241194

Keyword

nonn,frac

Author

N. J. A. Sloane, Apr 25 2014, based on a suggestion from Timothy Varghese.

Status

approved