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A113558
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Least multiple of n in which the n-th digit from left is 3.
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6
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3, 130, 123, 10032, 100030, 1000032, 1000013, 100000032, 100000053, 10000000030, 10000000043, 1000000000032, 1000000000103, 100000000000138, 1000000000000035, 10000000000000032, 10000000000000033, 1000000000000000134
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OFFSET
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1,1
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LINKS
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EXAMPLE
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a(4)= 10032, in which the fourth digit is 3.
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PROG
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(PARI) dig(n, digno, base) = { local(nshif) ; nshif=n ; for(shifr=0, digno-1, nshif = floor(nshif/base) ; ) ; nshif % base ; } ndig(n, base) = { local(nshif, resul) ; nshif=n ; resul=1 ; while(nshif>0, nshif = floor(nshif/base) ; if( nshif>0, resul++, break) ; ) ; return(resul) ; } { for (n = 1, 23, anmin=10^(n-1) ; if ( ( n % 2 == 0 ) || (n %5 == 0), anmin *= 10) ; if ( ( n % 20 == 0 ) || (n %50 == 0), anmin *= 10) ; for( nex = anmin, anmin+10000000000000000000000, if ( ( nex % n) != 0, next ; ) ; nexd=ndig(nex, 10) ; if( dig(nex, nexd-n, 10)==3, print(nex, ", ") ; break ; ) ; ); ) } \\ R. J. Mathar, Mar 15 2006
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CROSSREFS
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KEYWORD
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base,easy,nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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