A079466 Numbers k such that the "inventory" A063850 of k is a palindrome.
1, 22, 112, 121, 211, 333, 1113, 1131, 1311, 3111, 4444, 11114, 11141, 11411, 14111, 22233, 22323, 22332, 23223, 23232, 23322, 32223, 32232, 32322, 33222, 41111, 55555
Offset: 1
Examples
The "inventory" of 112 is 2112 (two "1"s, one "2"), which is a palindrome. Hence 112 belongs to the sequence.
Links
- Carlos Rivera, Puzzle 207. The Inventory Sequences and Self-Inventoried Numbers, The Prime Puzzles & Problems Connection.
Programs
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Mathematica
g[n_] := Module[{seen, r, d, l, i, t}, seen = {}; r = {}; d = IntegerDigits[n]; l = Length[d]; For[i = 1, i <= l, i++, t = d[[i]]; If[ ! MemberQ[seen, t], r = Join[r, IntegerDigits[Count[d, t]]]; r = Join[r, {t}]; seen = Append[seen, t]]]; FromDigits[r]]; isPalin[n_] := (n == FromDigits[Reverse[IntegerDigits[n]]]); Select[Range[10^5], isPalin[g[ # ]] &]