+- HP Forums (https://www.hpmuseum.org/forum)
+-- Forum: HP Software Libraries (/forum-10.html)
+--- Forum: General Software Library (/forum-13.html)
+--- Thread: (50g) OEIS A137580: Number of Different Digits in N! (/thread-9147.html)
(50g) OEIS A137580: Number of Different Digits in N! - Gerald H - 09-23-2017 12:16 PM
For natural number N input the programme returns the number of different digits in N!.
For info see
https://oeis.org/A137580
You may note that for N > 41 the programme returns 10 - this result is based on a heuristic proof of that fact. The proof is what I would call a 21st century proof &, while not satisfying those still entrenched in the 20th century, is more than adequate for moderns.
However, as moderns see everything open to revision, should a counter-proof appear I would amend the programme.
Code:
::
CK1&Dispatch
# FF
::
DUP
ZINT 41
Z>
casedrop
%10
PTR 2EF44
ZEROSWAP
FPTR2 ^Z>S
BINT10
ZERO_DO
DUPINDEX@
#>$
BINT1
POSCHR
#0=?SKIP
SWAP#1+SWAP
LOOP
DROP
UNCOERCE
;
;