A112748 Smallest prime of the form 4 followed by n copies of k.

41, 433, 4111, 47777, 42323232323, 4999999, 479797979797979, 43333333333333333, 4232323232323232323, 439393939393939393939, 48383838383838383838383, 4272727272727272727272727, 41111111111111

Offset

1,1

Links

Robert Israel, Table of n, a(n) for n = 1..250

Example

a(3) = 4111, 4 followed by three copies of 1.

Maple

cat3 := proc(a, b, n) local resu, i ; resu := a ; for i from 1 to n do resu := resu*10^( max(1, ilog10(b)+1) )+b ; od: RETURN(resu) ; end: A112748 := proc(n) local a, k; for k from 1 do a := cat3(4, k, n) ; if isprime(a) then RETURN(a) ; fi ; od: end: seq(A112748(n), n=1..20) ; # R. J. Mathar, Feb 08 2008

Crossrefs

Sequence in context: A083761 A209823 A196784 * A173768 A061643 A209842

Adjacent sequences: A112745 A112746 A112747 * A112749 A112750 A112751

Keyword

base,nonn

Author

Amarnath Murthy, Jan 02 2006

Extensions

More terms from R. J. Mathar, Feb 08 2008

Status

approved