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A162154 Odd terms are the number of consecutive prime numbers until a composite, even terms are the number of consecutive composite numbers until a prime. 2
2, 1, 1, 1, 1, 3, 1, 1, 1, 3, 1, 1, 1, 3, 1, 5, 1, 1, 1, 5, 1, 3, 1, 1, 1, 3, 1, 5, 1, 5, 1, 1, 1, 5, 1, 3, 1, 1, 1, 5, 1, 3, 1, 5, 1, 7, 1, 3, 1, 1, 1, 3, 1, 1, 1, 3, 1, 13, 1, 3, 1, 5, 1, 1, 1, 9, 1, 1, 1, 5, 1, 5, 1, 3, 1, 5, 1, 5, 1, 1, 1, 9, 1, 1, 1, 3, 1, 1, 1, 11, 1, 11, 1, 3, 1, 1, 1, 3, 1, 5, 1, 1, 1, 9 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(1)=2 because there are two consecutive primes (2 and 3), a(2)=1 (4), a(6)=3 (8,9,10).

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

FORMULA

a(2n)=A046933(n+1). - R. J. Mathar, Jun 27 2009

MATHEMATICA

Join[{2}, Riffle[Last[#]-First[#]-1&/@Partition[Prime[Range[2, 60]], 2, 1], 1]] (* Harvey P. Dale, Jun 04 2012 *)

CROSSREFS

Sequence in context: A063669 A319734 A211005 * A134505 A076933 A071974

Adjacent sequences:  A162151 A162152 A162153 * A162155 A162156 A162157

KEYWORD

nonn

AUTHOR

Claudio Meller, Jun 26 2009

STATUS

approved

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Last modified February 18 09:38 EST 2019. Contains 320249 sequences. (Running on oeis4.)