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 A146343 a(n) = smallest number k such that continued fraction of (1 + sqrt(k))/2 has period length n. 3
 5, 2, 17, 6, 41, 18, 89, 31, 73, 43, 265, 94, 421, 118, 193, 172, 521, 106, 241, 151, 337, 489, 433, 268, 929, 211, 409, 334, 673, 379, 937, 463, 601, 331, 769, 721, 2297, 619, 1033, 718, 1777, 394, 1753, 604, 1993, 634, 1249, 526, 3649, 694 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS T. D. Noe, Table of n, a(n) for n = 1..1000 MAPLE A := proc(n) local c; try c := numtheory[cfrac](1/2+sqrt(n)/2, 'periodic', 'quotients') ; RETURN(nops(c[2]) ); catch: RETURN(-1) end try ; end: A146343 := proc(n) for k from 1 do if A(k) = n then RETURN(k); fi; od: end: for n from 1 to 30 do printf("%d, ", A146343(n)) ; od: # R. J. Mathar, Nov 08 2008 MATHEMATICA nn = 50; t = Table[0, {nn}]; cnt = 0; k = 1; While[cnt < nn, k++; cf = ContinuedFraction[(1 + Sqrt[k])/2]; If[Head[cf[[-1]]] === List, len = Length[cf[[-1]]]; If[len <= nn && t[[len]] == 0, t[[len]] = k; cnt++]]]; t CROSSREFS Cf. A000290, A078370, A146326-A146345, A146348-A146360. Sequence in context: A281842 A282224 A282201 * A146363 A246797 A087958 Adjacent sequences:  A146340 A146341 A146342 * A146344 A146345 A146346 KEYWORD nonn AUTHOR Artur Jasinski, Oct 30 2008 EXTENSIONS a(6) changed to 18, a(25) to 929, a(28) to 334 by R. J. Mathar, Nov 08 2008 Extended by T. D. Noe, Mar 22 2011 STATUS approved

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Last modified August 2 02:53 EDT 2021. Contains 346409 sequences. (Running on oeis4.)