Triangular and Fibonacci Running Equality Expressions Generator

Searches for identities where the digits 1–9 (ascending), 9–1 (descending), or 9–0 (descending through zero) each appear exactly once, in strict order, split across an equals sign into two sides that evaluate to the same value k.

digits: 123456789  |  987654321  |  9876543210
ops: + − × ÷   ^   √ (up to 4 nested roots)   !   (a!)! (factorial applied twice)   T(n)   F(n)   parentheses   unary −

Examples with Triangular and Fibonacci functions:

881 := -9+8+7*(6+5!) = T(4)-T(T(F(3!)))-T(2)+T(T(10)) 881 := 1+2*F(3!)*T(T(4)) = -5+T(6)+F(F(7))+T(T(8))-F(9)
1010 := -1+2+3!+4^5-T(6) = T(7)*T(8)+F(sqrt(9)) 1010 := F(sqrt(9))+T(8)*T(7) = T(6)+5+4+T(T(3^2))-T(10)
Choose equality type

Select one or more equality structures to include in the search.

Choose operations

Basic operations and powers are always included. Add square roots and/or factorials.

Choose digit runs

Select one or more sequences to include in the search.

Choose special number functions

This choice is independent of Basic, square-root, and factorial operations.

Equality partitions split the digit run into contiguous, non-overlapping chunks (for example, a double equality may split 9 digits into three groups of 3) — every chunk still uses its digits exactly once, and no digit is ever shared between chunks. Double and triple equalities add search time because more partition points must be checked.

This only sets how many equations are shown per k when the search first finishes — every distinct equation the search actually finds for a k is stored and can be reached via the "showing" +/- control below, and downloads always include the full stored set, not just what's currently displayed. Results are ranked by a transparent complexity score, with the simplest verified identities first.

Click "Run search" to build the table. This runs entirely in your browser. Square-root, factorial, Triangular, and Fibonacci choices increase the search time; the progress line above shows which stage is running.