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%I #15 Dec 05 2016 13:38:36
%S 3,49,1020,28666,1099824,57520786,3882860433,331811494082
%N Number of cryptarithms of the form x + y = z in base n for which no summand contains any letter more than once and which have at least one solution.
%C Two cryptarithms are the same if one may be obtained from the other by a process of replacing letters and swapping the summands. For instance, the problem AB + BCD = DDD is the same as ABC + DA = CCC.
%C Solutions must assign a different digit to each letter, and numbers may not begin with 0.
%H Cryptarithms.com, <a href="http://www.cryptarithms.com/">Cryptarithms - Number Puzzles</a>
%H Math StackExchange, <a href="http://math.stackexchange.com/questions/1888311/how-many-strong-simple-addition-mathagrams-of-degree-one-are-there-in-a-given-ba">How many strong simple addition mathagrams of degree one are there in a given base?</a>
%H Eric M. Schmidt, <a href="/A277497/a277497.cpp.txt">C++ code to compute this sequence</a>
%H Eric M. Schmidt, <a href="/A277497/a277497.txt">List of solvable problems in base 3</a>
%e In base 10, the classic SEND + MORE = MONEY has an assignment of digits to the letters that makes the equation true, and is counted because neither SEND nor MORE contains a given letter more than once.
%e In base 3, CBA + AB = CAA is solvable, and is counted. There are exactly two solutions: (A = 1, B = 0, C = 2) and (A = 2, B = 0, C = 1).
%Y Cf. A277496.
%K nonn,base,hard,more
%O 2,1
%A _Eric M. Schmidt_, Oct 18 2016