The arithmetic correlations of two binary half‐ℓ‐sequences with connection integer pr, which is an odd prime power, are investigated. Possible values (of the arithmetic correlation) are calculated. In particular, if p ≡ 1 (mod 8), the authors prove that they are zero for non‐trivial shifts, that is, the half‐ℓ‐sequences have ideal arithmetic correlations. If p ≡ −1 (mod 8), an upper bound, which is of order of magnitude pr−1/2 ln p, is derived by using earlier results on the imbalance of half‐ℓ‐sequences with connection integer p studied by Gu and Klapper and later improved by Wang and Tan.