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A120273 Absolute value of the numerator of Sum[ (-1)^i * i/Prime[i], {i,1,n}]. 1
1, 1, 13, 29, 731, 4357, 136141, 1497401, 52856987, 698076077, 49526267143, 574253997269, 72925181864501, 1123720869207397, 143426539122302791, 2236629947933814637, 422054527184135696827, 8864360144543549996813 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

G. C. Greubel, Table of n, a(n) for n = 1..300

FORMULA

a(n) = Abs[ numerator[ Sum[ (-1)^i*i/Prime[i], {i,1,n}]]].

MATHEMATICA

Abs[Numerator[Table[Sum[(-1)^i*i/Prime[i], {i, 1, n}], {n, 1, 20}]]]

PROG

(PARI) for(n=1, 20, print1(numerator(abs(sum(k=1, n, (-1)^k*k/prime(k)))), ", ")) \\ G. C. Greubel, Aug 23 2018

(MAGMA) [Numerator(Abs((&+[(-1)^k*k/NthPrime(k): k in [0..n]]))): n in [1..20]]; // G. C. Greubel, Aug 23 2018

CROSSREFS

Sequence in context: A317897 A195878 A013545 * A104817 A048450 A216193

Adjacent sequences:  A120270 A120271 A120272 * A120274 A120275 A120276

KEYWORD

frac,nonn

AUTHOR

Alexander Adamchuk, Jul 01 2006

STATUS

approved

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Last modified October 18 10:55 EDT 2018. Contains 316321 sequences. (Running on oeis4.)