

A277497


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.


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 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 solvable problems in base 3


EXAMPLE

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.
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).


CROSSREFS

Cf. A277496.
Sequence in context: A203760 A208935 A202534 * A173174 A302466 A303248
Adjacent sequences: A277494 A277495 A277496 * A277498 A277499 A277500


KEYWORD

nonn,base,hard,more


AUTHOR

Eric M. Schmidt, Oct 18 2016


STATUS

approved



