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A002121 a(0) = 1, a(1) = 0, a(2) = -1; for n >= 3, a(n) = - a(n-2) + Sum_{ primes p with 3 <= p <= n} a(n-p).
(Formerly M0023 N0005)
2
1, 0, -1, 1, 1, -1, 0, 2, 0, -2, 2, 4, -3, -2, 8, 1, -8, 8, 12, -11, -4, 25, 4, -24, 21, 40, -31, -16, 82, 14, -81, 71, 131, -99, -48, 258, 46, -249, 223, 422, -303, -162, 825, 169, -791, 714, 1360, -955, -503, 2641, 573, -2479, 2263, 4365, -2941, -1592, 8436, 1978, -7830, 7212, 14083, -9133, -4992, 26970, 6688, -24590 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,8

COMMENTS

Arises in studying the Goldbach conjecture.

The last negative term appears to be a(303). - T. D. Noe, Dec 05 2006

REFERENCES

P. A. MacMahon, Properties of prime numbers deduced from the calculus of symmetric functions, Proc. London Math. Soc., 23 (1923), 290-316. [Coll. Papers, Vol. II, pp. 354-382] [The sequence g_n]

N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

LINKS

T. D. Noe, Table of n, a(n) for n = 0..1000

P. A. MacMahon, Properties of prime numbers deduced from the calculus of symmetric functions, Proc. London Math. Soc., 23 (1923), 290-316. = Coll. Papers, II, pp. 354-380.

Index entries for sequences related to Goldbach conjecture

FORMULA

G.f.: 1/(1+Sum_{k>0} (-x)^prime(k)). - Vladeta Jovovic, Mar 29 2003

PROG

(Haskell)

import Data.List (genericIndex)

a002121 n = genericIndex a002121_list n

a002121_list = 1 : 0 : -1 : f 0 (-1) 3 where

   f v w x = y : f w y (x + 1) where

     y = sum (map (a002121 . (x -)) $ takeWhile (<= x) a065091_list) - v

-- Reinhard Zumkeller, Mar 21 2014

CROSSREFS

Cf. A002100-A002125.

Cf. A065091.

Sequence in context: A308212 A181346 A300815 * A279158 A273166 A300822

Adjacent sequences:  A002118 A002119 A002120 * A002122 A002123 A002124

KEYWORD

sign,easy,look

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from Vladeta Jovovic, Mar 29 2003

Entry revised by N. J. A. Sloane, Dec 04 2006

STATUS

approved

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Last modified September 21 23:55 EDT 2019. Contains 327286 sequences. (Running on oeis4.)