A339673 - OEIS

%I #69 Apr 01 2021 21:25:58

%S 25427,31427,32027,32087,32093,37032,37583,37643,37693,49390,49501,

%T 50611,60490,60501,60611,61600,61601,61611,61711,61721,61722,62958,

%U 62959,62969,63069,64069,65427,72958,72959,72969,73069,73958,73959,73969,74058,74059,74068

%N Numbers that cannot be expressed as sum of at most nine repdigits numbers. One may not add two integers with the same repeated digit.

%C Computer solutions found by Oscar Volpatti.

%H Chai Wah Wu, <a href="/A339673/b339673.txt">Table of n, a(n) for n = 1..10000</a>

%H Carlos Rivera and Rodolfo Kurchan, <a href="http://www.primepuzzles.net/puzzles/puzz_1027.htm">Puzzle 1027. Integers as sum of distinct repdigits</a>, The prime puzzles & problems connection.

%e 8888 and 888 cannot be used in the same expression.

%e Examples: 25599 = 22222 + 3333 + 44, 98765 = 88888 + 7777 + 1111 + 555 + 333 + 99 + 2.

%e It appears that 987654 and 987650 cannot be expressed in this way.

%e 25427 is the smallest number without solution.

%e Smallest solution that ends with digits from 0 to 9 (solutions from Oscar Volpatti): 0: 49390 1: 49501 2: 37032 3: 32093 4: 143204 5: 254315 6: 74106 7: 25427 8: 62958 9: 62959.

%Y Cf. A235400.

%K base,nonn

%O 1,1

%A _Rodolfo Kurchan_, Jan 17 2021