OFFSET
0,1
COMMENTS
Any number occurring in this sequence occurs infinitely many times since the smallest such k for a specific n is also the smallest such k for all numbers formed by the concatenation of the initial digits after the decimal point in the decimal expansion of k*Pi.
From A266242, only 36 appears in this sequence. - Rémy Sigrist, Dec 01 2019
FORMULA
a(n) = 1 iff n belongs to A039916. - Rémy Sigrist, Dec 01 2019
EXAMPLE
For n = 0: The decimal expansion of 36*Pi starts 113.097335529232... and this is the smallest multiple of Pi where 0 occurs immediately after the decimal point, so a(0) = 36.
MATHEMATICA
a[n_]:=(k=1; While[Floor[(Pi*k-Floor[Pi*k])*10^Length[IntegerDigits[n]]]!=n, k++]; Return[k]); Table[a[n], {n, 0, 67}] (* Joshua Oliver, Dec 01 2019 *)
PROG
(PARI) pidigits(multipl, len) = floor((Pi*multipl - floor(Pi*multipl)) * 10^len)
a(n) = for(k=1, oo, if(pidigits(k, #Str(n))==n, return(k)))
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Felix Fröhlich, Dec 01 2019
STATUS
approved