cp's OEIS Frontend

A261396 a(n) = smallest k such that A260273(k) >= 2^n.

%I A261396 #19 Aug 31 2015 21:38:41
%S A261396 1,2,3,4,7,12,19,34,61,110,200,371,697,1310,2484,4739,9072,17458,
%T A261396 33671,65128,126225,244802,475124,922891,1793461,3487348,6784691,
%U A261396 13208038,25731600,50166771,97873783,191089176,373349780,729972649,1428257200,2796453078,5478981032,10741710906,21072415837
%N A261396 a(n) = smallest k such that A260273(k) >= 2^n.
%C A261396 The sequence indicates the first time a term in A260273 has binary length n+1.
%C A261396 A261646 = first differences = row lengths of tables A261644 and A261712. - _Reinhard Zumkeller_, Aug 30 2015
%o A261396 (Haskell)
%o A261396 a261396 n = a261396_list !! (n-1)
%o A261396 a261396_list = f 1 1 a260273_list where
%o A261396    f z k (x:xs) | x >= z    = k : f (2 * z) (k + 1) xs
%o A261396                 | otherwise = f z (k + 1) xs
%o A261396 -- _Reinhard Zumkeller_, Aug 30 2015
%Y A261396 Cf. A260273.
%Y A261396 Cf. A261646, A261644, A261712.
%K A261396 nonn
%O A261396 0,2
%A A261396 _N. J. A. Sloane_, Aug 17 2015
%E A261396 a(18)-a(23) from _Alois P. Heinz_, Aug 19 2015
%E A261396 a(24)-a(34) from _Chai Wah Wu_, Aug 26 2015
%E A261396 a(35)-a(38) from _Chai Wah Wu_, Aug 31 2015