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A122153 Decimal expansion of Parity Prime Constant: Sum_{k>=1} (-1)^(k+1) * 1/(2^prime(k)). 4
1, 4, 8, 8, 0, 9, 5, 5, 0, 7, 8, 8, 7, 7, 6, 2, 2, 4, 9, 6, 9, 5, 6, 8, 4, 6, 7, 8, 6, 6, 7, 9, 6, 5, 3, 1, 9, 8, 2, 2, 2, 4, 1, 3, 2, 8, 0, 8, 2, 1, 7, 0, 6, 7, 3, 7, 1, 7, 7, 0, 0, 0, 0, 5, 6, 3, 3, 1, 3, 9, 1, 2, 6, 2, 2, 3, 3, 3, 7, 4, 5, 1, 8, 4, 9, 4, 5, 1, 4, 3, 7, 7, 8, 8, 8, 0, 8, 5, 2 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Binary expansion is given in A071986(n) = pi(n) mod 2.

LINKS

Table of n, a(n) for n=0..98.

FORMULA

Equals Sum_{k>=1} (-1)^(k+1) * 1/(2^prime(k)).

Equals lim_{n->infinity} A122150(n)/A034765(n).

EXAMPLE

0.148809550788776224969568467866796531982224132808217067371770000563313912...

MATHEMATICA

RealDigits[Sum[(-1)^(k+1)*1/2^Prime[k], {k, 1, 1000}], 10, 100]

PROG

(PARI) suminf(k=1, (-1)^(k+1) * 1/2^prime(k)) \\ Michel Marcus, Mar 20 2019

CROSSREFS

Cf. A034765, A122150, A122151, A122152, A122153, A071986, A000720.

Sequence in context: A135863 A176221 A021676 * A200628 A202245 A153258

Adjacent sequences:  A122150 A122151 A122152 * A122154 A122155 A122156

KEYWORD

nonn,cons

AUTHOR

Alexander Adamchuk, Aug 22 2006

EXTENSIONS

Offset corrected by R. J. Mathar, Feb 05 2009

Edited by Michel Marcus, Mar 20 2019

STATUS

approved

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Last modified August 19 04:27 EDT 2019. Contains 326109 sequences. (Running on oeis4.)