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A241189 Numerator of Sum_{i=1..n} 1/(prime(i)*prime(i+1)). 5
1, 7, 11, 127, 1693, 29243, 561623, 13019431, 379503437, 11809225121, 438235268123, 18007758091069, 775817745542929, 36524284093223105, 1938403609207158571, 2160165866032831207, 131893095784520401909, 8844093116997411126541, 628373208972323386101329, 45900898298568589325230523 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(371) has 1002 decimal digits. - Michael De Vlieger, Jan 27 2016

LINKS

Michael De Vlieger, Table of n, a(n) for n = 1..370

EXAMPLE

1/6, 7/30, 11/42, 127/462, 1693/6006, 29243/102102, 561623/1939938, 13019431/44618574, 379503437/1293938646, 11809225121/40112098026, 438235268123/1484147626962, ...

MAPLE

g:= n-> add(1/(ithprime(i)*ithprime(i+1)), i=1..n);

t1:=[seq(g(n), n=1..20)];

t1a:=map(numer, t1); # A241189

t1b:=map(denom, t1); # A241190

MATHEMATICA

Table[Numerator@ Sum[1/(Prime[i + 1] Prime@ i), {i, n}], {n, 20}] (* Michael De Vlieger, Jan 27 2016 *)

CROSSREFS

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

See also A061015/A061742, A115963/A115964.

Sequence in context: A018680 A107187 A132958 * A057737 A130704 A038543

Adjacent sequences:  A241186 A241187 A241188 * A241190 A241191 A241192

KEYWORD

nonn,frac

AUTHOR

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

STATUS

approved

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Last modified January 19 18:13 EST 2020. Contains 331051 sequences. (Running on oeis4.)