OFFSET
0,2
LINKS
Reinhard Zumkeller, Table of n, a(n) for n = 0..60
Onno M. Cain and Sela T. Enin, Inventory Loops (i.e. Counting Sequences) have Pre-period 2 max S_1 + 60, arXiv:2004.00209 [math.NT], 2020.
EXAMPLE
One; one one; three ones; four ones, one three; six ones, two threes, one four; eight ones, one two, three threes, two fours, one six; eleven ones, three twos, five threes, three fours, two sixes, one eight; thirteen [note not 15] ones, five twos, eight threes, four fours, one five, three sixes, two eights, one eleven [note than numbers >9 are preserved as wholes rather than as a collection of digits]; etc.
MATHEMATICA
FromDigits /@ Nest[Append[#, Flatten@ Map[Reverse, Tally@ Sort@ Flatten@ # ] ] &, {{1}}, 10] (* Michael De Vlieger, Jul 15 2020 *)
PROG
(Haskell)
import Data.List (group, sort, transpose)
a060857 n = a060857_list !! n
a060857_list = 1 : f [1] :: [Integer] where
f xs = (read $ concatMap show ys) : f (xs ++ ys) where
ys = concat $ transpose [map length zss, map head zss]
zss = group $ sort xs
-- Reinhard Zumkeller, Jan 25 2014
(Python)
def summarize_lst(lst):
ans = []
for d in sorted(set(lst)): ans += [lst.count(d), d]
return ans
def aupton(nn):
alst, arunninglst = [1], [1]
for n in range(nn):
nxt_lst = summarize_lst(arunninglst)
arunninglst += nxt_lst
alst.append(int("".join(map(str, nxt_lst))))
return alst
print(aupton(10)) # Michael S. Branicky, Jan 11 2021
CROSSREFS
KEYWORD
base,nice,nonn
AUTHOR
Henry Bottomley, May 03 2001
STATUS
approved