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

1,1

Links

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

Example

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

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 *)

Crossrefs

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

Sequence in context: A088199 A140010 A122723 * A142894 A141909 A296187

Adjacent sequences: A089783 A089784 A089785 * A089787 A089788 A089789

Keyword

base,nonn

Author

Amarnath Murthy, Nov 24 2003

Extensions

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

Status

approved