A153223 Numbers k such that the string k is found at position k-4 in the decimal digits of Pi.
9, 233, 1614, 9218, 27755974, 81259258, 120526011, 238732548, 651265325, 783609697
Offset: 1
Examples
a(1) = 9 because 9 occurs at offset (9-4) after the decimal in the digits of Pi.
Programs
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Python
from sympy import S # download https://stuff.mit.edu/afs/sipb/contrib/pi/pi-billion.txt, then #with open('pi-billion.txt', 'r') as f: pi_digits = f.readline() pi_digits = str(S.Pi.n(3*10**5+2))[:-2] # alternative to above pi_digits = pi_digits.replace(".", "") def afind(): for k in range(5, len(pi_digits)): sk = str(k) if sk == pi_digits[k-4:k-4+len(sk)]: print(k, end=", ") afind() # Michael S. Branicky, Jan 30 2022
Extensions
a(5)-a(10) from Michael S. Branicky, Jan 30 2022