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 A237661 Indices of records in A237660. 3
 3, 42, 75, 151, 2730, 7281, 14563, 174762, 184111, 932067, 11184810, 13256071, 26512143, 715827882, 1908874353 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Table of n, a(n) for n=1..15. Charles R Greathouse IV, C code to find initial terms MATHEMATICA With[{s = Table[If[AllTrue[#, EvenQ], 0, SelectFirst[Reverse@ #, OddQ]] &@ Most@ Rest@ NestWhileList[If[EvenQ@ #, #/2, (3 # + 1)/2] &, n, # > 1 &], {n, 2, 10^5}] }, 1 + Values[#][[All, 1]] &@ Rest@ KeySort@ PositionIndex@ s] (* Michael De Vlieger, Aug 14 2017 *) PROG (C) See Greathouse link (PARI) A237660(n)=my(k); if(n%2, n=3*n+1); n>>=valuation(n, 2); if(n==1, return(0)); k=n; while(1, n+=(n+1)>>1; n>>=valuation(n, 2); if(n==1, return(k), k=n)) r=0; for(n=1, 1e8, t=A237660(n); if(t>r, r=t; print1(n", "))) \\ Charles R Greathouse IV, Aug 14 2017 CROSSREFS Cf. A237660. Sequence in context: A057013 A055755 A249046 * A116006 A079826 A112291 Adjacent sequences: A237658 A237659 A237660 * A237662 A237663 A237664 KEYWORD nonn,more AUTHOR Kival Ngaokrajang, Feb 11 2014 EXTENSIONS a(11)-a(15) from Charles R Greathouse IV, Aug 14 2017 STATUS approved

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Last modified April 23 23:26 EDT 2024. Contains 371917 sequences. (Running on oeis4.)