A114786 Smallest prime of the form: one or more 4's followed by prime(n) (or 0 if no such prime exists).

0, 43, 0, 47, 44444444444444411, 44444444413, 44417, 419, 4423, 4444444429, 431, 444444437, 4441, 443, 4447, 44453, 44444459, 461, 467, 4444471, 444473, 479, 4483, 44444489, 44497, 44101, 444444103, 444444444444107, 444109, 444113, 4127

Offset

1,2

Comments

Prime(n) is all 0's followed by prime(n). a(n) is all 4's followed by prime(n). Conjecture: No term is zero for n > 3.

a(346) = 0 or a(346) > 5000, but note a(892) = 3612. - D. S. McNeil, Feb 04 2011

Links

Table of n, a(n) for n=1..31.

Example

a(7) = 44417, as prime(7) = 17 and both 417 and 4417 are composite.

Mathematica

Table[If[n==1||n==3, 0, Select[FromDigits/@(Join[#, IntegerDigits[Prime[n]]]& /@ (Table[PadLeft[{4}, k, 4], {k, 50}])), PrimeQ, 1][[1]]], {n, 35}]  (* Harvey P. Dale, Feb 03 2011 *)

Crossrefs

Cf. A114783, A114784, A114785.

Sequence in context: A173866 A291871 A357001 * A139424 A051318 A036202

Adjacent sequences: A114783 A114784 A114785 * A114787 A114788 A114789

Keyword

base,nonn

Author

Amarnath Murthy, Nov 17 2005

Extensions

More terms from Joshua Zucker, May 06 2006

Edited by Jon E. Schoenfield, May 19 2019

Status

approved