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A110194
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First differences of A110095 (least nonprime sequence whose first differences are nonprime).
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0
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1, 8, 1, 4, 1, 1, 4, 1, 1, 4, 1, 1, 4, 1, 1, 1, 1, 4, 4, 1, 1, 4, 1, 1, 4, 1, 1, 4, 1, 1, 1, 1, 4, 4, 1, 1, 1, 1, 4, 4, 1, 1, 4, 1, 1, 1, 1, 4, 4
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| Conjecture: from a(5) on, are there only substrings <1 1 4> and <1 1 1 1 4 4 >?
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EXAMPLE
| Beginning with 1, we have to add 8 in order to get the first nonprime number (all other numbers <8 are prime or giving a prime). So 1+8=9 for a(2).
Then add 1=10 for a(3).
Then add (not 1 because 11 is prime; nor 2 and 3 because they are prime) ...add 4=14 for a(4), etc.
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CROSSREFS
| Cf. A110095 and twin-primes related sequences.
Sequence in context: A011469 A140457 A176457 * A199283 A079359 A010156
Adjacent sequences: A110191 A110192 A110193 * A110195 A110196 A110197
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KEYWORD
| easy,nonn
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AUTHOR
| Alexandre Wajnberg & Eric Angelini (alexandre.wajnberg(AT)ulb.ac.be), Sep 06 2005
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