A085732 Smallest number obtained by placing a + in the first n digits of decimal expansion of Pi.

4, 17, 72, 329, 473, 1906, 9067, 40680, 124068, 340694, 579517, 2967748, 9677489, 36774905, 85005719, 350057197, 673138588, 3731385891, 9039525037, 40395250381, 121209164997, 412091649984, 1293483111622, 3934831116232

Offset

2,1

Links

Reinhard Zumkeller, Table of n, a(n) for n = 2..1000

Dave Andersen, The Pi-Search Page.

Eric Weisstein's World of Mathematics, Pi.

Example

n=5: insert '+' in '31415':
a(5) = Min{3+1415=1418, 31+415=446, 314+15=329, 3141+5=3146} = 329.

Prog

(Haskell)
import Data.List (inits, tails); import Data.Function (on)
a085732 n = a085732_list !! (n-2)
a085732_list = map f $ drop 2 $ inits $ concatMap show a000796_list
   where f xs = minimum $ init $ tail $
                zipWith (on (+) read) (inits xs) (tails xs)
-- Reinhard Zumkeller, May 02 2015

Crossrefs

Cf. A000796.

Sequence in context: A257388 A113442 A362908 * A289159 A083330 A255632

Adjacent sequences: A085729 A085730 A085731 * A085733 A085734 A085735

Keyword

nonn,base

Author

Reinhard Zumkeller, Jul 20 2003

Status

approved