# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a053087 Showing 1-1 of 1 %I A053087 #14 Feb 03 2023 01:35:11 %S A053087 0,1,3,2,5,4,5,3,7,6,5,7,6,8,7,4,9,8,7,8,9,6,9,8,9,7,9,10,8,10,9,5,11, %T A053087 10,9,10,8,10,11,9,10,11,7,11,10,11,9,11,10,11,12,8,11,10,12,11,9,12, %U A053087 11,12,10,12,11,6,13,12,11,12,10,12,11,12,13,9,12,11,13,12,10 %N A053087 a(n) is the smallest j for which 2^j kara n is defined (see A053405). %H A053087 Reinhard Zumkeller, Table of n, a(n) for n = 1..1000 %e A053087 a(6)=4 because 2^3 kara 6 is undefined, but 16 kara 6 = 3. %o A053087 (Haskell) %o A053087 a053087 n = head [j | j <- [0..], (2 ^ j) `kara` n /= Nothing] where %o A053087 kara a b = if null ks then Nothing else Just $ head ks %o A053087 where ks = [c | c <- [1..a], a <= c * b, a > c * (b - 1)] %o A053087 -- _Reinhard Zumkeller_, Mar 30 2013 %Y A053087 Cf. A053405. %Y A053087 A053092(n) = 2^a(n) kara n. %K A053087 nonn,look %O A053087 1,3 %A A053087 Robert Lozyniak (11(AT)onna.com), Feb 26 2000 %E A053087 More terms from Antony M. Goddard, cat(AT)animal.u-net.com or tony(AT)noggin.lowtech.org, Oct 13 2000 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE