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 A175217 The second nonprimes after the primes. 0

%I

%S 6,6,8,9,14,15,20,21,25,32,33,39,44,45,49,55,62,63,69,74,75,81,85,91,

%T 99,104,105,110,111,115,129,133,140,141,152,153,159,165,169,175,182,

%U 183,194,195,200,201,213,225,230,231,235,242,243,253,259,265,272,273,279

%N The second nonprimes after the primes.

%F a(n) = prime(n)+2 + A010051(prime(n)+1) + A010051(prime(n)+2) + A010051(prime(n)+3). [From _Reinhard Zumkeller_, Mar 29 2010]

%t b[n_] := Boole[PrimeQ[n]];

%t a[n_] := With[{p = Prime[n]}, p + 2 + b[p + 1] + b[p + 2] + b[p + 3]];

%t Array[a, 59] (* _Jean-François Alcover_, Nov 12 2017, after _Reinhard Zumkeller_ *)

%K nonn,easy

%O 1,1

%A _Jaroslav Krizek_, Mar 06 2010

%E More terms from _Reinhard Zumkeller_, Mar 29 2010

%E Typos in data corrected by _Jean-François Alcover_, Nov 12 2017

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Last modified June 24 14:24 EDT 2021. Contains 345417 sequences. (Running on oeis4.)