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+--- Thread: (50G) Characteristic Function of OEIS A053432 (/thread-5006.html)
(50G) Characteristic Function of OEIS A053432 - Gerald H - 10-25-2015 06:47 AM
https://oeis.org/A053432
lists the numbers having digits read left to right in alphabetic order in English reading 0 as "zero".
The programme below for integer input returns a 1. if the number is in the sequence A053432, 0. otherwise.
I doubt the programme can be improved & would be pleased to be proven wrong.
Alternative algorithms welcome.
Code:
::
CK1&Dispatch
# FF
::
BINT0
"549176320"
ROT
FPTR2 ^Z>S
DUPLEN$
ZERO_DO
2DUP
CAR$
BINT1
POSCHR
DUP4UNROLL
5ROLL
#<ITE
ExitAtLOOP
CDR$
LOOP
ROTROT2DROP
NULL$?
COERCEFLAG
;
;