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Search: id:A131377
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| A131377 |
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Starting with 1, the sequence a(n) changes from 1 to 0 or back when the next number n is a prime. |
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+0
3
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| 1, 1, 0, 1, 1, 0, 0, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 0, 0, 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, 0, 0, 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, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0
(list; graph; listen)
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OFFSET
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0,1
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EXAMPLE
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n = 0, 1, 2, 3, 4, 5, etc..
a(n)= 1, 1, 0, 1, 1, 0, etc.
Starting with 1 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.
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MAPLE
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P:=proc(n) local i, k; k:=1; 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);
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CROSSREFS
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Cf. A131378.
Sequence in context: A079559 A014577 A157926 this_sequence A077049 A124895 A089885
Adjacent sequences: A131374 A131375 A131376 this_sequence A131378 A131379 A131380
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KEYWORD
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easy,nonn
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AUTHOR
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Paolo P. Lava & Giorgio Balzarotti (ppl(AT)spl.at), Jul 04 2007
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