A153221 Numbers k such that the string k is found at position k-3 in the decimal digits of Pi.

51, 875, 62843, 242424, 4308765, 9710721, 24747689, 126987778

Offset

1,1

Links

Table of n, a(n) for n=1..8.

Example

a(1) = 51 because 51 occurs at offset (51-3) after the decimal in the digits of Pi.

Prog

(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 ispal(s): return s == s[::-1]
def afind():
    for k in range(len(pi_digits)):
        sk = str(k)
        if sk == pi_digits[k-3:k-3+len(sk)]:
            print(k, end=", ")
afind() # Michael S. Branicky, Jan 30 2022

Crossrefs

Cf. A057679, A057680, A109513, A109514, A153223, A153224.

Sequence in context: A201832 A317651 A201212 * A172639 A231648 A017767

Adjacent sequences: A153218 A153219 A153220 * A153222 A153223 A153224

Keyword

base,more,nonn

Author

Gil Broussard, Dec 21 2008

Extensions

a(5)-a(8) from Michael S. Branicky, Jan 30 2022

Status

approved