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A068698 Smallest primes in the reverse concatenation of n odd numbers. +0
1
3, 31, 0, 59575553, 15131197, 0, 55535149474543, 6361595755535149, 0, 1151131111091071051031019997, 207205203201199197195193191189187, 0, 65636159575553514947454341, 4543413937353331292725232119, 0 (list; graph; listen)
OFFSET

1,1

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: A115040 A065594 A059232 this_sequence A053300 A089281 A090543

Adjacent sequences: A068695 A068696 A068697 this_sequence A068699 A068700 A068701

KEYWORD

base,hard,nonn

AUTHOR

Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Mar 04 2002

EXTENSIONS

More terms from Sascha Kurz (sascha.kurz(AT)uni-bayreuth.de), Mar 27 2002

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Last modified September 6 16:04 EDT 2008. Contains 143483 sequences.


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