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 A072961 Numbers using only the digits 2 and 5, or numbers that are both curved and linear. 9

%I

%S 2,5,22,25,52,55,222,225,252,255,522,525,552,555,2222,2225,2252,2255,

%T 2522,2525,2552,2555,5222,5225,5252,5255,5522,5525,5552,5555,22222,

%U 22225,22252,22255,22522,22525,22552,22555,25222,25225,25252,25255

%N Numbers using only the digits 2 and 5, or numbers that are both curved and linear.

%D M. J. Halm, Three Boxes, Puzzle-M Magazine (Apr. 1987).

%H Vincenzo Librandi, <a href="/A072961/b072961.txt">Table of n, a(n) for n = 1..8190</a>

%t Flatten[Table[FromDigits/@Tuples[{2, 5}, n], {n, 5}]] (* _Vincenzo Librandi_, Aug 19 2016 *)

%o (Python)

%o from itertools import product

%o A072961_list = [int(''.join(a)) for l in range(1,11) for a in product('25',repeat=l)] # _Chai Wah Wu_, May 12 2016

%o (MAGMA) [n: n in [1..30000] | Set(Intseq(n)) subset {2,5}]; // _Vincenzo Librandi_, Aug 19 2016

%K easy,nonn,base

%O 1,1

%A _Michael Joseph Halm_, Aug 13 2002

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Last modified September 23 04:54 EDT 2020. Contains 337295 sequences. (Running on oeis4.)