The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A030459 Prime p concatenated with next prime is also prime. 25
 2, 31, 83, 151, 157, 167, 199, 233, 251, 257, 263, 271, 331, 353, 373, 433, 467, 509, 523, 541, 601, 653, 661, 677, 727, 941, 971, 1013, 1033, 1181, 1187, 1201, 1223, 1259, 1367, 1453, 1459, 1657, 1669, 1709, 1741, 1861, 1973, 2069, 2161 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Terms 157, 257, 263, 541, 1187, 1459, 2179 also belong to A030460. - Carmine Suriano, Jan 27 2011 All terms, except for the first one, must be either in A185934 or in A185935, i.e., have the same residue (mod 6) as the subsequent prime. - M. F. Hasler, Feb 06 2011 LINKS M. F. Hasler and Charles R Greathouse IV, Table of n, a(n) for n = 1..10000 (first 4110 terms from Hasler) FORMULA a(n) = A151799(A030460(n)). A030461(n) = concat(a(n), A030460(n)) = A045533(A000720(a(n))). MATHEMATICA Select[Prime[Range[500]], PrimeQ[FromDigits[Join[IntegerDigits[#], IntegerDigits[ NextPrime[#]]]]]&] (* Harvey P. Dale, Jun 20 2011 *) PROG (PARI) o=2; forprime(p=3, 1e4, isprime(eval(Str(o, o=p))) & print1(precprime(p-1)", "))  \\ M. F. Hasler, Feb 06 2011 CROSSREFS See A030461 for the concatenated primes. Cf. A000720, A030460, A045533, A151799. Sequence in context: A054207 A104095 A282725 * A141978 A212569 A101254 Adjacent sequences:  A030456 A030457 A030458 * A030460 A030461 A030462 KEYWORD nonn,base AUTHOR STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified May 15 01:50 EDT 2021. Contains 343909 sequences. (Running on oeis4.)