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 Four generations (Posted on 2020-07-06)
Let S be a set of all six-digit integers.

Let S1 be a subset of S, including all members of S such that each consists
of distinct digits.
Let S2 be a subset of S1, including all members of S1 each with 5 being the difference between its largest digit and its lowest one.
Let S3 be a subset of S2, comprising all elements of S2 divisible by 143.

What is the cardinality of S3 ?

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 part 1 via computer | Comment 1 of 9
There are  none  Why?

lord@rabbit-3 ~ % i143

total cnt =            0

lord@rabbit-3 ~ more i143.f

program i134

implicit none

integer cnt,i,k,kk,a,dum,dum1,d(6),maxd,mind

cnt=0

do 1 i=1,6993

a=143*i

dum=a

mind=10

maxd=-1

do  k=1,6

dum1=(dum/10)*10

d(k)=dum-dum1

if(d(k).lt.mind)mind=d(k)

if(d(k).gt.maxd)maxd=d(K)

dum=dum/10

if(k.gt.1)then

do kk=1,k-1

if(d(kk).eq.d(k))go to 1

enddo

endif

enddo

if((maxd-mind).eq.5)cnt=cnt+1

1          enddo

print*,' total cnt = ',cnt

end

Edited on July 6, 2020, 9:30 am
 Posted by Steven Lord on 2020-07-06 09:29:31

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