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A287300 Primes that can be generated by the concatenation in base 3, in ascending order, of two consecutive integers read in base 10. 1
5, 31, 41, 61, 71, 281, 337, 421, 449, 617, 673, 701, 2297, 2543, 2707, 2789, 2953, 3527, 3691, 4019, 5003, 5167, 5413, 5659, 5741, 5987, 6151, 6397, 21961, 22937, 23669, 24889, 25621, 26597, 27329, 27817, 28549, 28793, 30013, 31477, 31721, 32941, 34649, 35381 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..44.

EXAMPLE

1 and 2 in base 3 are 1 and 2 and concat(1,2) = 12 in base 10 is 5;

3 and 4 in base 3 are 10 and 11 and concat(10,11) = 1011 in base 10 is 31.

MAPLE

with(numtheory): P:= proc(q, h) local a, b, c, d, k, n; a:=convert(q+1, base, h); b:=convert(q, base, h); c:=[op(a), op(b)]; d:=0; for k from nops(c) by -1 to 1 do d:=h*d+c[k]; od; if isprime(d) then d; fi; end: seq(P(i, 3), i=1..1000);

MATHEMATICA

With[{b = 3}, Select[Map[FromDigits[Flatten@ IntegerDigits[#, b], b] &, Partition[Range@ 150, 2, 1]], PrimeQ]] (* Michael De Vlieger, May 23 2017 *)

CROSSREFS

Cf. A000040, A030458.

Sequence in context: A027761 A166306 A341632 * A162665 A130474 A238674

Adjacent sequences: A287297 A287298 A287299 * A287301 A287302 A287303

KEYWORD

nonn,base,easy

AUTHOR

Paolo P. Lava, May 23 2017

STATUS

approved

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Last modified December 6 04:57 EST 2022. Contains 358594 sequences. (Running on oeis4.)