A287244 Indices n for which concatenation of the numbers from n to n + 9 is prime.

4, 20, 68, 88, 122, 140, 188, 200, 212, 220, 224, 244, 254, 374, 460, 490, 502, 518, 550, 568, 632, 688, 734, 814, 832, 884, 898, 908, 928, 982, 1022, 1108, 1472, 1490, 1498, 1514, 1544, 1580, 1894, 1954, 2074, 2230, 2294, 2384, 2492, 2524, 2722

Offset: 1

Author

XU Pingya, May 22 2017

Keywords

• base
• easy
• nonn

Examples

			a(1) = 4, since 45678910111213 is prime.
		

Links

• Robert Israel, Table of n, a(n) for n = 1..10000
• F. Smarandache, Sequences of Numbers Involved in Unsolved Problems.
• Eric Weisstein's World of Mathematics, Smarandache Sequences

Crossrefs

Cf. A030458.

Programs

Maple

filter:= proc(n) isprime(parse(cat($n .. n+9))) end proc:
select(filter, 2*[$1..10^4]); # Robert Israel, Jan 08 2024

Mathematica

Position[Map[FromDigits@ Flatten@ IntegerDigits@ # &, Partition[Range@ 2800, 10, 1]], p_ /; PrimeQ@ p][[All, 1]] (* Michael De Vlieger, May 22 2017 *)