A089786 Primes of the form prime(2k) followed by prime(k).

73, 197, 7129, 10141, 15161, 19379, 271109, 373157, 593251, 757331, 983431, 997433, 1069463, 1231547, 1361599, 1531661, 1571683, 1627727, 1831811, 2069911, 2161967, 2213977, 24731093, 25311103, 26931193, 27131213, 27911237, 28191259

Offset: 1

Author

Amarnath Murthy, Nov 24 2003

Keywords

• base
• nonn

Examples

			10141 is a term as a concatenation of prime(26)=101 followed by prime(13)=41.
		

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A089782, A089783, A089784, A089785, A089787.

Programs

Maple

a:=proc(k) local s,m: s:= [op(convert(ithprime(k),base,10)),op(convert(ithprime(2*k),base,10))]: m:=add(s[j]*10^(j-1),j=1..nops(s)): if not isprime(m) then RETURN(NULL) else RETURN(m) fi: end; seq(a(k),k=1..250); (C. Ronaldo)

Mathematica

Select[Table[FromDigits[Flatten[IntegerDigits/@{Prime[2n],Prime[n]}]],{n,250}],PrimeQ] (* Harvey P. Dale, Nov 17 2014 *)

Extensions

Corrected and extended by C. Ronaldo (aga_new_ac(AT)hotmail.com), Dec 25 2004