A096099 a(0) = 1, a(n) = least number such that the concatenation of all terms through a(n) is divisible by prime(n).

1, 2, 3, 5, 5, 2, 13, 25, 8, 22, 16, 26, 35, 35, 11, 26, 48, 58, 6, 46, 4, 77, 83, 29, 33, 187, 61, 78, 81, 23, 183, 15, 22, 68, 8, 137, 84, 178, 99, 7, 71, 82, 142, 241, 133, 71, 56, 19, 32, 318, 157, 199, 303, 16, 201, 201, 213, 257, 355, 229, 365, 379, 345, 27, 52, 19, 272

Offset

0,2

Comments

Related sequence: numbers k such that a(k) > prime(k): 7, 21, 22, 25, 30, 37, 43, 49, 52, 58, 60, 61, 62 ... (E.g., 7 would be a term since a(7) = 25 > prime(7) = 17.) [edited by Jon E. Schoenfield, Nov 19 2018]

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Example

a(7) = 25 as the concatenation a(1),a(2),...,a(6),a(7) = 1235521325 == 0 (mod 17), prime(7) = 17.

Mathematica

s = "1"; Print[s]; Do[k = 1; While[Mod[ToExpression[s <> ToString[k]], Prime[n]] != 0, k++ ]; Print[k]; s = s <> ToString[k], {n, 1, 100}] (* Ryan Propper, Sep 03 2005 *)

Crossrefs

Cf. A073893.

Sequence in context: A264047 A264035 A082876 * A019780 A227833 A133293

Adjacent sequences: A096096 A096097 A096098 * A096100 A096101 A096102

Keyword

base,nonn

Author

Amarnath Murthy, Jun 24 2004

Extensions

a(10)-a(66) from Ryan Propper, Sep 03 2005

Status

approved