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 A110194 First differences of A110095 (least nonprime sequence whose first differences are nonprime). 1
 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, 1, 1, 4, 1, 1, 4, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 4, 4, 1, 1, 4, 1, 1, 1, 1, 1, 1, 1, 1, 4, 1, 1, 1, 1, 4, 1, 1, 4, 4, 1, 1, 4, 1, 1, 4, 1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Conjecture: from a(5) on, are there only substrings <1 1 4> and <1 1 1 1 4 4 >? LINKS Table of n, a(n) for n=1..95. 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. PROG (PARI) lista(nn) = my(va = vector(nn), last=0); for (n=1, nn, my(new = last+1); while(isprime(new) || isprime(new-last), new++); va[n] = new-last; last = new; ); va; \\ Michel Marcus, Aug 09 2022 CROSSREFS Cf. A110095 and twin-primes related sequences. Sequence in context: A140457 A358286 A176457 * A199283 A079359 A010156 Adjacent sequences: A110191 A110192 A110193 * A110195 A110196 A110197 KEYWORD easy,nonn AUTHOR Alexandre Wajnberg and Eric Angelini, Sep 06 2005 EXTENSIONS More terms from Michel Marcus, Aug 09 2022 STATUS approved

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Last modified September 23 21:37 EDT 2023. Contains 365554 sequences. (Running on oeis4.)