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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

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Last modified January 27 09:05 EST 2023. Contains 359838 sequences. (Running on oeis4.)