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+--- Thread: (50g) OEIS A008904: Last Non-Zero Digit of Factorial (/thread-9022.html)
(50g) OEIS A008904: Last Non-Zero Digit of Factorial - Gerald H - 09-09-2017 05:54 PM
For input N , a natural number, the programme returns the Nth element in the series
https://oeis.org/A008904
NB This series does NOT become periodic.
Size: 228.5
CkSum: # 3597h
Code:
::
CK1&Dispatch
# FF
::
'
::
DUP
ZINT 2
Z<
casedrop
ZINT 1
{
ZINT 6
ZINT 6
ZINT 12
ZINT 36
ZINT 24
ZINT 24
ZINT 24
ZINT 48
ZINT 24
ZINT 36
}
OVER
ZINT 10
FPTR2 ^ZMod
FPTR2 ^Z2BIN
#1+
NTHCOMPDROP
ZINT 3
ROT
ZINT 5
FPTR2 ^ZQUOText
DUP4UNROLL
ZINT 4
FPTR2 ^ZMod
FPTR2 ^Z2BIN
FPTR2 ^RP#
FPTR2 ^RMULText
SWAP
1GETLAM
EVAL
FPTR2 ^RMULText
ZINT 10
FPTR2 ^ZMod
;
1LAMBIND
1GETLAM
EVAL
ABND
;
;RE: (50g) OEIS A008904: Last Non-Zero Digit of Factorial - Gerald H - 09-11-2017 08:54 PM
Here a smaller & much faster version of the programme:
Size: 185.5
CkSum: # E8F9h
Code:
::
CK1&Dispatch
# FF
::
'
::
DUP
ZINT 2
Z<
casedrop
BINT1
{
BINT6
BINT6
BINT12
BINT36
BINT24
BINT24
BINT24
BINT48
BINT24
BINT36
}
OVER
ZINT 10
FPTR2 ^ZMod
FPTR2 ^Z2BIN
#1+
NTHCOMPDROP
{
BINT1
BINT3
BINT9
BINT27
}
ROT
ZINT 5
FPTR2 ^ZQUOText
DUP4UNROLL
ZINT 4
FPTR2 ^ZMod
FPTR2 ^Z2BIN
#1+
NTHCOMPDROP
#*
SWAP
1GETLAM
EVAL
#*
BINT10
#/
DROP
;
DUP1LAMBIND
EVAL
ABND
FPTR2 ^#>Z
;
;RE: (50g) OEIS A008904: Last Non-Zero Digit of Factorial - Gerald H - 09-23-2017 03:17 PM
A shorter & quicker programme:
Code:
::
CK1&Dispatch
# FF
::
DUP
Z2_
Z<
casedrop
Z1_
Z2_
ZEROZERO
4ROLL
BEGIN
Z5_
FPTR2 ^ZDIVext
FPTR2 ^Z>#
DUP
4ROLL
DUP#1+
5UNROLL
#*
SWAP
BINT2
#/
SWAP
#0=ITE
#+
DROP
4ROLL
#+
UNROTDUP
Z0_
EQUAL
UNTIL
2DROP
BINT4
#/
DROP
FPTR2 ^RP#
DUP
Z1_
EQUALNOT
?SEMI
DROP
Z6_
;
;