A114757 Smallest prime of the form: n successive positive integers in ascending order followed by a 9. a(3k) = 0 as no such prime exists.

19, 239, 0, 23459, 345679, 0, 23456789, 234567899, 0, 2345678910119, 6789101112131415169, 0, 313233343536373839404142439, 36373839404142434445464748499, 0, 123456789101112131415169

Offset

1,1

Links

Table of n, a(n) for n=1..16.

Example

a(4) = 23459, four successive positive integers 2,3,4,5 in ascending order followed by a 9.

Mathematica

a[n_]:=If[Mod[n, 3]==0, 0, (For[m=1, (v={}; Do[v=Join[v, IntegerDigits[k]], {k, m, m+n-1}]); !PrimeQ[10FromDigits[v]+9], m++ ]; 10FromDigits[v]+9)]; Table[a[n], {n, 17}] - Farideh Firoozbakht
f[n_] := Block[{t = Range@n}, If[ Mod[n, 3] == 0, 0, While[p = FromDigits@Flatten@IntegerDigits@Join[t, {9}]; !PrimeQ@p, t++ ]; p]]; Array[f, 16] (* Robert G. Wilson v *)

Crossrefs

Cf. A114754, A114755, A114756, A114758, A114759, A112716, A108145.

Sequence in context: A022033 A025938 A229026 * A142615 A021814 A299864

Adjacent sequences: A114754 A114755 A114756 * A114758 A114759 A114760

Keyword

base,nonn

Author

Amarnath Murthy, Jan 01 2006

Extensions

Extended by Robert G. Wilson v, Ray Chandler and Farideh Firoozbakht, Jan 02 2006

Status

approved