A239974 Primes which are a concatenation of prime(k+4), prime(k+2) and prime(k) for some k.

1373, 433729, 615343, 797161, 837367, 897971, 149137127, 193181173, 227211197, 337317311, 367353347, 401389379, 443433421, 557541521, 577569557, 587571563, 757743733, 811797773, 823811797, 10191009991, 10211013997, 116311511123, 120111871171, 130713011291

Offset: 1

Author

K. D. Bajpai, Mar 30 2014

Keywords

• nonn
• base

Comments

All the terms in the sequence are primes which are a reverse concatenation of prime(k), prime(k+2) and prime(k+4) for some k.

Examples

			1373 is a prime and appears in the sequence because it is the concatenation of prime(2+4), prime(2+2) and prime(2).
433729 is a prime and appears in the sequence because it is the concatenation of prime(10+4), prime(10+2) and prime(10).
		

Links

• K. D. Bajpai, Table of n, a(n) for n = 1..3742

Crossrefs

Cf. A000040, A030461, A030469, A030473, A086040, A086041, A239789.

Programs

Maple

with(StringTools): KD := proc() local a, b, d, e; a:=ithprime(n+4); b:=ithprime(n+2); d:=ithprime(n);  e:= parse(cat(a, b, d)); if isprime(e) then RETURN (e); fi; end: seq(KD(), n=1..500);

Mathematica

Select[Table[FromDigits[Flatten[{IntegerDigits[Prime[n+4]],IntegerDigits[Prime[n+2]], IntegerDigits[Prime[n]]}]], {n,1,500}], PrimeQ]