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A121559 Find r1 = n modulo p1, where p1 is the largest prime not greater than n. Then find r2 = r1 modulo p2, where p2 is the largest prime not greater than r1. Repeat until the last r is either 1 or 0; a(n) is the last r value. 4
1, 0, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The sequence has the form of blocks of 0's between 1's. See sequence A121560 for the lengths of the blocks of zeros.

LINKS

Kerry Mitchell, Table of n, a(n) for n = 1..7919

EXAMPLE

a(9) = 0 because 7 is the largest prime not larger than 9, 9 mod 7 = 2, 2 is the largest prime not greater than 2 and 2 mod 2 = 0.

CROSSREFS

Cf. A121560, A121561, A121562.

Sequence in context: A101266 A105367 A065043 * A004641 A100810 A174889

Adjacent sequences:  A121556 A121557 A121558 * A121560 A121561 A121562

KEYWORD

easy,nonn

AUTHOR

Kerry Mitchell, Aug 07 2006

STATUS

approved

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Last modified April 19 08:09 EDT 2014. Contains 240739 sequences.