LINKS
Chai Wah Wu, <a href="/A007055/b007055_1.txt">Table of n, a(n) for n = 0..6617</a>
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Chai Wah Wu, <a href="/A007055/b007055_1.txt">Table of n, a(n) for n = 0..6617</a>
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Chai Wah Wu, <a href="/A007055/b007055_1.txt">Table of n, a(n) for n = 0..6617</a>
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Chuan Guo, J. Shallit, and A. M. Shur, <a href="http://arxiv.org/abs/1503.09112">On the Combinatorics of Palindromes and Antipalindromes</a>, arXiv preprint arXiv:1503.09112 [cs.FL], 2015.
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(Python)
from functools import lru_cache
from sympy import totient, proper_divisors
@lru_cache(maxsize=None)
def A007055(n): return (n<<(n+1>>1) if n&1 else 3*n<<(n-2>>1))-sum(totient(n//d)*A007055(d) for d in proper_divisors(n, generator=True)) if n else 1 # Chai Wah Wu, Feb 18 2024
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