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A153225 Numbers k such that the string k modulo 100 is found at position k in the decimal digits of Pi. 1

%I #10 Jan 30 2022 23:05:17

%S 1,102,104,189,193,256,302,407,467,475,503,594,702,712,751,804,881,

%T 905,978,998,1005,1053,1104,1107,1154,1275,1303,1306,1307,1315,1421,

%U 1502,1600,1604,1690,1694,1706,1802,1860,1904,1907,1908,2006,2025,2105,2146,2208

%N Numbers k such that the string k modulo 100 is found at position k in the decimal digits of Pi.

%H Michael S. Branicky, <a href="/A153225/b153225.txt">Table of n, a(n) for n = 1..10000</a>

%e a(4) = 189 because 89 occurs at offset 189 after the decimal in the digits of Pi.

%o (Python)

%o from sympy import S

%o # download https://stuff.mit.edu/afs/sipb/contrib/pi/pi-billion.txt, then

%o #with open('pi-billion.txt', 'r') as f: pi_digits = f.readline()

%o pi_digits = str(S.Pi.n(3*10**5+2))[:-2] # alternative to above

%o pi_digits = pi_digits.replace(".", "")

%o def ispal(s): return s == s[::-1]

%o def agen():

%o for k in range(len(pi_digits)):

%o sk = str(k%100)

%o if sk == pi_digits[k:k+len(sk)]:

%o yield k

%o g = agen()

%o print([next(g) for n in range(1, 48)]) # _Michael S. Branicky_, Jan 30 2022

%Y Cf. A000796, A057679, A057680, A109513, A109514.

%K base,nonn

%O 1,2

%A _Gil Broussard_, Dec 21 2008

%E a(47) and beyond from _Michael S. Branicky_, Jan 30 2022

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Last modified July 18 09:18 EDT 2024. Contains 374378 sequences. (Running on oeis4.)