A253443 Smallest missing number within the first n terms in A109890.

4, 4, 5, 5, 5, 5, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 34, 37, 37, 37, 37, 37

Offset: 4

Author

Reinhard Zumkeller, Jan 01 2015

Keywords

• nonn

Comments

A253584(n) occurs exactly A253444(n) times.

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 4..10000

Crossrefs

Cf. A095258, A095259, A253444 (run lengths), A253584 (range), A253415.

Programs

Haskell

import Data.List (insert)
a253443 n = a253443_list !! (n-4)
a253443_list = f (4, []) 6 where
   f (m,ys) z = g $ dropWhile (< m) $ a027750_row' z where
     g (d:ds) | elem d ys = g ds
              | otherwise = m : f (ins [m, m+1 ..] (insert d ys)) (z + d)
     ins (u:us) vs'@(v:vs) = if u < v then (u, vs') else ins us vs
-- Reinhard Zumkeller, Jan 03 2015