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A277496
Number of cryptarithms of the form x + y = z in base n for which no summand contains any letter more than once and for which the solution is unique.
2
3, 43, 909, 25264, 946088, 49916876, 3402999604, 295506405205
OFFSET
2,1
COMMENTS
Two cryptarithms are the same if one may be obtained from the other by a process of replacing letters and/or swapping the summands. For instance, the problem AB + BCD = DDD is the same as ABC + DA = CCC.
Solutions must assign a different digit to each letter, and numbers may not begin with 0.
EXAMPLE
In base 10, the classic SEND + MORE = MONEY has a unique 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.
In base 3, CBA + CAB = AAA has a unique solution (A = 2, B = 0, C = 1), and so is counted.
CROSSREFS
Cf. A277497.
Sequence in context: A350924 A141060 A361878 * A302218 A302664 A201784
KEYWORD
nonn,base,hard,more
AUTHOR
Eric M. Schmidt, Oct 18 2016
STATUS
approved