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A175217 The second nonprimes after the primes. 0
6, 6, 8, 9, 14, 15, 20, 21, 25, 32, 33, 39, 44, 45, 49, 55, 62, 63, 69, 74, 75, 81, 85, 91, 99, 104, 105, 110, 111, 115, 129, 133, 140, 141, 152, 153, 159, 165, 169, 175, 182, 183, 194, 195, 200, 201, 213, 225, 230, 231, 235, 242, 243, 253, 259, 265, 272, 273, 279 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..59.

FORMULA

a(n) = prime(n)+2 + A010051(prime(n)+1) + A010051(prime(n)+2) + A010051(prime(n)+3). [From Reinhard Zumkeller, Mar 29 2010]

MATHEMATICA

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

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

Array[a, 59] (* Jean-François Alcover, Nov 12 2017, after Reinhard Zumkeller *)

CROSSREFS

Sequence in context: A201578 A322292 A195707 * A000509 A160257 A315830

Adjacent sequences:  A175214 A175215 A175216 * A175218 A175219 A175220

KEYWORD

nonn,easy

AUTHOR

Jaroslav Krizek, Mar 06 2010

EXTENSIONS

More terms from Reinhard Zumkeller, Mar 29 2010

Typos in data corrected by Jean-François Alcover, Nov 12 2017

STATUS

approved

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Last modified April 18 02:37 EDT 2021. Contains 343072 sequences. (Running on oeis4.)