A113890
Smallest prime of the form: all eights followed by prime(n). a(n)> prime(n). 0 if no such prime exists.
Original entry on oeis.org
0, 83, 0, 887, 811, 88813, 88817, 8819, 823, 829, 8831, 8837, 88888841, 88843, 88888888888888888888888888888847, 853, 859, 8861, 8867, 888871, 88873, 88888879, 883, 88888888888889, 88897, 8101, 888103, 8888107, 888109
Offset: 1
a(4) = 887, as 87 is composite, prime(4) = 7.
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cat2 := proc(a,b) a*10^(max(1,ilog10(b)+1))+b ; end: A002282 := proc(n) 8*(10^n-1)/9 ; end: A113890 := proc(n) local p,a,n8 ; p := ithprime(n) ; for n8 from 1 to 120 do a := cat2(A002282(n8),p) ; if isprime(a) then return(a) ; fi ; od: RETURN(0) ; end: seq(A113890(n),n=1..35) ; # R. J. Mathar, Jan 31 2008
A113889
Smallest prime of the form: all sevens followed by prime(n); a(n) > prime(n); or 0 if no such prime exists.
Original entry on oeis.org
0, 73, 0, 0, 77711, 77713, 7717, 719, 7723, 77777777777777777729, 77731, 777737, 7741, 743, 77747, 7753, 7759, 761, 77777777767, 7777777777771, 773, 777777777777777777777777777777777777777777777777777777777777777779
Offset: 1
a(9) = 7723, as 723 is composite, prime(9) = 23.
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Join[{0,73,0,0},Flatten[Select[#,PrimeQ,1]&/@Table[FromDigits[ PadLeft[ IntegerDigits[n],i,7]],{n,Prime[Range[5,30]]},{i,IntegerLength[ n]+1, 100}]]] (* Harvey P. Dale, Nov 20 2013 *)
More terms from Joshua Albert (jba138(AT)psu.edu), Jan 20 2006
A113891
Smallest prime of the form: all nines followed by prime(n) with a(n) > prime(n); or 0 if no such prime exists.
Original entry on oeis.org
0, 0, 0, 97, 911
Offset: 1
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