A153227 - OEIS

%I #13 Jan 30 2022 15:58:57

%S 5,95,171,529,1913,2753,60597,831092,9552919

%N Numbers k such that the string k is found at position 2k in the decimal digits of Pi.

%e a(2) = 95 because 95 occurs at offset 190 (2*95) 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 afind():

%o     for k in range(1, len(pi_digits)):

%o         sk = str(k)

%o         if sk == pi_digits[2*k:2*k+len(sk)]:

%o             print(k, end=", ")

%o afind() # _Michael S. Branicky_, Jan 30 2022

%Y Cf. A057679, A057680, A109513, A109514, A153228.

%K base,more,nonn

%O 1,1

%A _Gil Broussard_, Dec 21 2008

%E a(8) corrected by _Paul Tek_, Jun 09 2013

%E a(9) from _Michael S. Branicky_, Jan 30 2022