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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 (list; graph; refs; listen; history; text; internal format)
 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. LINKS Cryptarithms.com, Cryptarithms - Number Puzzles Eric M. Schmidt, C++ code to compute this sequence Eric M. Schmidt, List of uniquely solvable problems in base 3 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: A299506 A350924 A141060 * A302218 A302664 A201784 Adjacent sequences: A277493 A277494 A277495 * A277497 A277498 A277499 KEYWORD nonn,base,hard,more AUTHOR Eric M. Schmidt, Oct 18 2016 STATUS approved

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Last modified December 8 11:05 EST 2022. Contains 358693 sequences. (Running on oeis4.)