A287313 Primes that can be generated by the concatenation in base 9, in descending order, of two consecutive integers read in base 10.

19, 29, 59, 79, 89, 983, 1229, 1721, 2131, 2213, 2377, 2459, 3361, 3607, 3853, 4099, 4591, 4673, 4919, 5657, 5821, 5903, 6067, 60589, 64969, 65699, 70079, 72269, 76649, 78839, 83219, 86869, 91249, 94169, 95629, 102199, 102929, 107309, 108769, 113149, 117529, 118259

Offset

1,1

Links

Table of n, a(n) for n=1..42.

Example

1 and 2 in base 9 are 1 and 2 and concat(21) = 21 in base 10 is 19;
8 and 9 in base 9 are 8 and 10 and concat(10,8) = 108 in base 10 is 89.

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

Mathematica

With[{b = 9}, Select[Map[FromDigits[Flatten@ IntegerDigits[#, b], b] &, Reverse /@ Partition[Range[0, 165], 2, 1]], PrimeQ]] (* Michael De Vlieger, May 25 2017 *)

Crossrefs

Cf. A000040, A052089.

Sequence in context: A141311 A090148 A348561 * A136071 A088998 A181606

Adjacent sequences: A287310 A287311 A287312 * A287314 A287315 A287316

Keyword

nonn,base,easy

Author

Paolo P. Lava, May 24 2017

Status

approved