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

 

Logo

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 56th year, we are closing in on 350,000 sequences, and we’ve crossed 9,700 citations (which often say “discovered thanks to the OEIS”).

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A104718 Concatenations of pairs of primes that differ by 8. 6
311, 513, 1119, 2331, 2937, 5361, 5967, 7179, 8997, 101109, 131139, 149157, 173181, 191199, 233241, 263271, 269277, 359367, 389397, 401409, 431439, 449457, 479487, 491499, 563571, 569577, 593601, 599607, 653661, 683691, 701709, 719727, 743751 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

There are no primes in this sequence after a(1) = 311, as all values thereafter are divisible by 3. Semiprimes in this sequence include: a(3) = 1119 = 3 * 373 a(6) = 5361 = 3 * 1787, a(8) = 7179 = 3 * 2393, a(9) = 8997 = 3 * 2999, a(10) = 101109 = 3 * 33703, a(13) = 173181 = 3 * 57727, a(15) = 233241 = 3 * 77747, a(17) = 269277 = 3 * 89759, a(21) = 431439 = 3 * 143813, a(26) = 569577 = 3 * 189859, a(35) = 821829 = 3 * 273943.

LINKS

Table of n, a(n) for n=1..33.

FORMULA

a(n) = A023202(n) concatenated with A023202(n)+8.

CROSSREFS

Cf. A000040, A001358, A023202, A103195, A103206, A104719.

Sequence in context: A142626 A142950 A323050 * A142576 A025024 A173596

Adjacent sequences:  A104715 A104716 A104717 * A104719 A104720 A104721

KEYWORD

base,easy,nonn

AUTHOR

Jonathan Vos Post, Mar 20 2005

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.

License Agreements, Terms of Use, Privacy Policy. .

Last modified November 30 19:02 EST 2021. Contains 349424 sequences. (Running on oeis4.)