A065840
Numbers n such that the first n quaternary digits found in the base-10 expansion of Pi form a prime (when the decimal point is ignored).
Original entry on oeis.org
1, 2, 3, 5, 10, 19, 72, 115, 220, 315, 375, 12408
Offset: 1
E.g., the first a(5) or 10 quaternary digits of Pi are 31.12332323{4} and 3112332323{4} is the prime 880571{10}.
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p = First[ RealDigits[ Pi, 10, 10^5]]; p = p[[ Select[ Range[10^5], p[[ # ]] == 0 || p[[ # ]] == 1 || p[[ # ]] == 2 || p[[ # ]] == 3 & ]]]; Do[ If[ PrimeQ[ FromDigits[ Take[p, n], 4]], Print[ n]], {n, 1, 4000} ]
A065832
Numbers k such that the first k binary digits found in the base-10 expansion of Pi form a prime (when the decimal point is ignored).
Original entry on oeis.org
2, 4, 10, 24, 29, 34, 43, 62, 76, 351, 778, 2736, 4992, 7517, 22044, 40390, 204505
Offset: 1
The first a(3)=10 binary digits of Pi are 1101110001_2 which is prime 881_10.
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p = First[ RealDigits[ Pi, 10, 10^5]]; p = p[[ Select[ Range[10^5], p[[ # ]] == 0 || p[[ # ]] == 1 & ]]]; Do[ If[ PrimeQ[ FromDigits[ Take[p, n], 2]], Print[n]], {n, 1, Length[p] } ]
Original entry on oeis.org
3, 13, 881, 14436001, 461952047, 14782465513, 7568622343067, 3968137871002260679, 65013970878501038966321
Offset: 1
Original entry on oeis.org
3, 13, 53, 859, 880571, 230836658783, 18727694659923768688081143062632211180505377, 1448985191439414787314128433365601157107793684026416650771108564122239
Offset: 1
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