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A112749 Smallest prime of the form 5 followed by n copies of some digit k. 1
53, 577, 5333, 59999, 511111, 5111111111111, 59999999, 577777777, 5171717171717171717, 59999999999, 52727272727272727272727, 5111111111111, 53333333333333, 577777777777777, 5111111111111111 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..15.

EXAMPLE

a(3) = 5333, 5 followed by three copies of 3.

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: A112749 := proc(n) local a, k; for k from 1 do a := cat3(5, k, n) ; if isprime(a) then RETURN(a) ; fi ; od: end: seq(A112749(n), n=1..20) ; # R. J. Mathar, Feb 08 2008

CROSSREFS

Sequence in context: A177120 A165555 A201855 * A245589 A177141 A096707

Adjacent sequences:  A112746 A112747 A112748 * A112750 A112751 A112752

KEYWORD

base,nonn

AUTHOR

Amarnath Murthy, Jan 02 2006

EXTENSIONS

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

STATUS

approved

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Last modified February 25 08:42 EST 2020. Contains 332221 sequences. (Running on oeis4.)