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 A071293 a(0)=1, a(n) is the smallest integer > a(n-1) such that the continued fraction for 1/a(0)+1/a(1)+1/a(2)+...+1/a(n) contains exactly 2^n elements. 0
 1, 2, 5, 11, 573, 71081, 506860777 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS EXAMPLE The continued fraction for 1/a(0)+1/a(1)+1/5 = 1+1/2+1/5 is {1, 1, 2, 3} which contains 2^2 elements. 5 is the smallest integer > 2 with this property, hence a(2)=5. PROG (PARI) s=1; t=1; for(n=1, 5, s=s+1/t; while(abs(2^n-length(contfrac(s+1/t)))>0, t++); print1(t, ", ")) CROSSREFS Sequence in context: A069504 A158997 A101828 * A234572 A341804 A109623 Adjacent sequences:  A071290 A071291 A071292 * A071294 A071295 A071296 KEYWORD hard,nonn AUTHOR Benoit Cloitre, Jun 11 2002 EXTENSIONS One more term from Michel ten Voorde Jun 13 2003 STATUS approved

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Last modified April 11 10:52 EDT 2021. Contains 342886 sequences. (Running on oeis4.)