A287311 Primes that can be generated by the concatenation in base 8, in descending order, of two consecutive integers read in base 10.

17, 53, 71, 1039, 1429, 1559, 1949, 2339, 2729, 3119, 3769, 4159, 33857, 34883, 40013, 41039, 48221, 50273, 54377, 58481, 61559, 63611, 69767, 70793, 74897, 76949, 84131, 86183, 89261, 96443, 100547, 101573, 104651, 106703, 110807, 111833, 112859, 117989, 120041

Offset

1,1

Links

Table of n, a(n) for n=1..39.

Example

1 and 2 in base 8 are 1 and 2 and concat(2,1) = 21 in base 10 is 17;
7 and 8 in base 8 are 7 and 10 and concat(10,7) = 107 in base 10 is 71.

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, 8), i=0..1000);

Mathematica

With[{b = 8}, Select[Map[FromDigits[Flatten@ IntegerDigits[#, b], b] &, Reverse /@ Partition[Range[0, 250], 2, 1]], PrimeQ]] (* Michael De Vlieger, May 25 2017 *)

Crossrefs

Cf. A000040, A052089.

Sequence in context: A061242 A062343 A176254 * A285225 A044119 A044500

Adjacent sequences: A287308 A287309 A287310 * A287312 A287313 A287314

Keyword

nonn,base,easy

Author

Paolo P. Lava, May 24 2017

Status

approved