

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




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

Table of n, a(n) for n=2..9.
Cryptarithms.com, Cryptarithms  Number Puzzles
Math StackExchange, How many strong simple addition mathagrams of degree one are there in a given base?
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



