editing

approved

a(n) <= A000217(n).

(Haskell)

import Data.List (elemIndex); import Data.Maybe (maybe)

a247799 n = a247799_list !! n

a247799_list = 0 : f 1 [0] where

f x zs@(z:_) = y : f (x + 1) (y : zs) where

y = z + maybe x id (elemIndex x $ reverse zs)

Cf. A000217.

allocateda(0) = 1; a(n) = a(n-1) + (if n = a(k) for some k then k Reinhardelse Zumkellern).

0, 1, 3, 5, 9, 12, 18, 25, 33, 37, 47, 58, 63, 76, 90, 105, 121, 138, 144, 163, 183, 204, 226, 249, 273, 280, 306, 333, 361, 390, 420, 451, 483, 491, 525, 560, 596, 605, 643, 682, 722, 763, 805, 848, 892, 937, 983, 993, 1041, 1090, 1140, 1191, 1243, 1296

0,3

Reinhard Zumkeller, <a href="/A247799/b247799.txt">Table of n, a(n) for n = 0..1000</a>

allocated

nonn

Reinhard Zumkeller, Sep 26 2014

approved

editing

allocated for Reinhard Zumkeller

allocated

approved