A099052 All palindromes of length greater than 1 in the decimal expansion of e, ordered by the ending position of the palindrome. Multiple terms ending at the same position are ordered by the starting position of the palindrome.

828, 18281, 818, 28182, 8281828, 828, 353, 747, 66, 2662, 77, 757, 99, 999, 99, 959, 595, 66, 9669, 696, 676, 77, 2772, 66, 303, 353, 535, 525, 66, 66, 919, 39193, 99, 181, 66, 33, 595, 323, 232, 434, 94349, 323, 33, 88, 525, 101, 11, 383, 99, 88, 4884, 44

Offset: 1

Author

Matthew Howells (mathmatt(AT)gmail.com), Nov 13 2004

Keywords

• nonn
• base

Links

• Michael S. Branicky, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A001113 (e).

Programs

Python

from sympy import E
def ispal(s): return all(s[i] == s[-1-i] for i in range(len(s)//2))
def aupto(maxdigs):
    digits_e = str(E.n(maxdigs+4))[2:]
    return [int(s) for s in (digits_e[j:k+1] for k in range(1, maxdigs)
        for j in range(k)) if s[0] != '0' and ispal(s)]
print(aupto(240)) # Michael S. Branicky, Jun 28 2021

Extensions

Offset changed and a(50) and beyond from Michael S. Branicky, Jun 28 2021