A065830 -id:A065830 - cp's OEIS frontend

A065831 Primes found in A065830.

Original entry on oeis.org

3, 13, 881, 14436001, 461952047, 14782465513, 7568622343067, 3968137871002260679, 65013970878501038966321

Offset: 1

Patrick De Geest, Nov 24 2001

Jinyuan Wang, Table of n, a(n) for n = 1..12
K. Brown, MathPages 184 [Wrong link]

Cf. A000796, A011545, A011546, A039954, A048796, A055143, A005042, A060421, A065828-A065840.

a(n) = A065830(A065832(n)). - Jinyuan Wang, Aug 31 2021

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

Patrick De Geest, Nov 24 2001

In other words, take the decimal expansion of Pi, drop any digits greater than 1, omit the decimal point and look for prefixes in the resulting string which form base-2 primes.

Numbers k such that A065830(k) is prime.

			The first a(3)=10 binary digits of Pi are 1101110001_2 which is prime 881_10.

Cf. A065828 up to A065840, A000796, A011545, A011546, A055143, A005042, A060421, A039954, A048796.

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] } ]

More terms from Robert G. Wilson v, Nov 30 2001
a(15)-a(16) from Chai Wah Wu, Apr 06 2020
a(17) from Michael S. Branicky, Sep 25 2024

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A065831 Primes found in A065830.

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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).

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