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A068698 Smallest primes in the reverse concatenation of n odd numbers. 0
3, 31, 0, 59575553, 15131197, 0, 55535149474543, 6361595755535149, 0, 1151131111091071051031019997, 207205203201199197195193191189187, 0, 65636159575553514947454341, 4543413937353331292725232119, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

EXAMPLE

a(5) = 15131197 is a prime and a concatenation of 15,13,11,9 and 7.

MAPLE

for n from 1 to 32 do d := 0:c := true: if((n mod 3)=0) then c := false:a := 0:end if: while(c=true) do a := 2*(n+d)-1:for j from 1 to n-1 do a := 2*(n+d-j)-1+10^( floor(evalf(log(2*(n+d-j)-1)/log(10))+0.0000000001 )+1)*a:end do: if(isprime(a))then c := false:end if:d := d+1:end do:b[n] := a:end do:seq(b[h], h=1..32);

CROSSREFS

Sequence in context: A155731 A145385 A059232 * A053300 A322777 A089281

Adjacent sequences:  A068695 A068696 A068697 * A068699 A068700 A068701

KEYWORD

base,hard,nonn

AUTHOR

Amarnath Murthy, Mar 04 2002

EXTENSIONS

More terms from Sascha Kurz, Mar 27 2002

STATUS

approved

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Last modified August 8 05:50 EDT 2020. Contains 336290 sequences. (Running on oeis4.)