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 A131378 Starting with 0, the sequence a(n) changes from 0 to 1 or back when the next number n is a prime. 3
 0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS Zero together with A071986 - Omar E. Pol, Feb 19 2011. LINKS EXAMPLE n = 0, 1, 2, 3, 4, 5, etc.. a(n)= 0, 0, 1, 0, 0, 1, etc. Starting with 0 the sequence changes when we move from 1 to 2 because 2 is prime, again from 2 to 3 because also 3 is prime, then from 4 to 5 being 5 prime and so on. MAPLE P:=proc(n) local i, k; k:=0; for i from 0 by 1 to n do if isprime(i) then if k=1 then k:=0; else k:=1; fi; fi; print(k); od; end: P(100); CROSSREFS Cf. A131377. Cf. A071986 - Omar E. Pol, Feb 19 2011. Sequence in context: A116178 A028999 A091244 * A014707 A106138 A064990 Adjacent sequences:  A131375 A131376 A131377 * A131379 A131380 A131381 KEYWORD easy,nonn AUTHOR Paolo P. Lava and Giorgio Balzarotti, Jul 04 2007 STATUS approved

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Last modified July 21 14:38 EDT 2017. Contains 289642 sequences.