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A156781 Primes : if sums of prime number and 2 consecutive prime numbers on-left-and-on-right are also primes. 5
11, 17, 23, 29, 31, 41, 61, 71, 79, 157, 211, 281, 293, 311, 349, 389, 401, 463, 509, 661, 719, 757, 797, 809, 857, 863, 997, 1187, 1201, 1289, 1291, 1301, 1307, 1319, 1399, 1427, 1451, 1663, 1669, 1723, 2029, 2111, 2113, 2129, 2137, 2243, 2311, 2339, 2341 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

5+7+11=23(prime);11+13+17=41(prime),... prime(n)+prime(n-1)+prime(n-2) are primes and prime(n)+prime(n+1)+prime(n+2) are also primes.

LINKS

Table of n, a(n) for n=1..49.

MATHEMATICA

lst={}; Do[p0=Prime[n+0]; p1=Prime[n+1]; p2=Prime[n+2]; p3=Prime[n+3]; p4=Prime[n+4]; If[PrimeQ[p0+p1+p2]&&PrimeQ[p2+p3+p4], AppendTo[lst, p2]], {n, 6!}]; lst

CROSSREFS

Sequence in context: A106563 A106574 A171125 * A175888 A209624 A243153

Adjacent sequences:  A156778 A156779 A156780 * A156782 A156783 A156784

KEYWORD

nonn

AUTHOR

Vladimir Joseph Stephan Orlovsky, Feb 15 2009

STATUS

approved

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Last modified March 5 11:57 EST 2021. Contains 341823 sequences. (Running on oeis4.)