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 A111421 a(n) = n-th decimal digit + 1 of the fraction formed by the square root of the n-th prime. 0
 5, 4, 7, 8, 3, 2, 7, 5, 4, 2, 4, 9, 9, 1, 5, 3, 8, 5, 0, 4, 2, 5, 3, 1, 5, 2, 9, 7, 5, 0, 9, 9, 2, 5, 4, 5, 1, 9, 5, 2, 1, 3, 9, 7, 4, 3, 4, 8, 5, 8, 7, 7, 3, 6, 1, 2, 3, 4, 2, 4, 8, 5, 5, 8, 8, 5, 4, 7, 0, 7, 2, 3, 2, 0, 9, 0, 5, 3, 0, 0, 4, 6, 7, 0, 1, 5, 0, 4, 9, 7, 0, 7, 4, 7, 5, 3, 7, 4, 6, 0, 4, 8, 9, 0, 7 (list; graph; refs; listen; history; text; internal format)
 OFFSET 2,1 COMMENTS Also a Cantor diagonal proving the irrational numbers are a non-denumerable infinite set. Also A071901(n)+ 1. REFERENCES John D. Barrow, The Infinite Book, Pantheon Book New York 2005, pp. 69-76. LINKS EXAMPLE The 2nd prime is 3. Sqrt(3) = 1.7320508..., The 2nd entry after the decimal point is 3 and 3+1=4, the 2nd entry in the table. MATHEMATICA f[n_] := Block[{rd = RealDigits[ Sqrt@Prime@n, 10, 111]}, Mod[rd[[1, n + rd[[2]]]] + 1, 10]]; Array[f, 105] (* Robert G. Wilson v *) PROG (PARI) cantor(n) = \Cantor proof of the non-denumerable infinity of real numbers { local(x, y, j=2, z); forprime(x=2, n, y=eval(Vec(Str(frac(sqrt(x))))); j++; z=(y[j]+1) % 10; print1(z", "); ); } CROSSREFS Cf. A071901. Sequence in context: A194362 A103549 A011285 * A252666 A245073 A021650 Adjacent sequences:  A111418 A111419 A111420 * A111422 A111423 A111424 KEYWORD easy,nonn,base AUTHOR Cino Hilliard, Nov 12 2005 EXTENSIONS More terms from Robert G. Wilson v, Nov 17 2005 STATUS approved

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Last modified January 21 11:57 EST 2019. Contains 319355 sequences. (Running on oeis4.)