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A287303 Primes that can be generated by the concatenation in base 4, in descending order, of two consecutive integers read in base 10. 0
19, 101, 271, 1429, 1559, 1949, 2339, 2729, 3119, 3769, 4159, 17989, 18503, 19531, 21587, 24671, 27241, 29297, 30839, 32381, 33409, 33923, 36493, 44203, 47287, 51913, 55511, 64763, 286999, 289049, 293149, 295199, 301349, 305449, 323899, 332099, 336199, 350549, 375149 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
EXAMPLE
3 and 4 in base 4 are 3 and 10 and concat(10,3) = 103 in base 10 is 19;
5 and 6 in base 4 are 11 and 12 and concat(12,11) = 1211 in base 10 are 101.
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, 4), i=1..1000);
MATHEMATICA
With[{b = 4}, Select[Map[FromDigits[Flatten@ IntegerDigits[#, b], b] &, Reverse /@ Partition[Range[0, 370], 2, 1]], PrimeQ]] (* Michael De Vlieger, May 23 2017 *)
CROSSREFS
Sequence in context: A241236 A044270 A044651 * A142216 A027005 A061696
KEYWORD
nonn,base,easy
AUTHOR
Paolo P. Lava, May 23 2017
STATUS
approved

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Last modified July 17 17:52 EDT 2024. Contains 374377 sequences. (Running on oeis4.)