A126844 - OEIS

%I #12 Jan 06 2025 01:22:47

%S 1,2173,252,725,436,543,832,994,601,521,741,349,73,2002,22,683,1434,

%T 955,1576,1929,949,1989,1727,30,1354,445,1855,1222,768,1669,1273,2091,

%U 2184,736,247,719,1472,1722,820,575,2177,1391,2104,1157,593,295,66,750,1987

%N Ramanujan numbers (A000594) read mod 13^3.

%H Amiram Eldar, <a href="/A126844/b126844.txt">Table of n, a(n) for n = 1..10000</a>

%H H. P. F. Swinnerton-Dyer, <a href="http://dx.doi.org/10.1007/978-3-540-37802-0_1">On l-adic representations and congruences for coefficients of modular forms</a>, pp. 1-55 of Modular Functions of One Variable III (Antwerp 1972), Lect. Notes Math., 350, 1973.

%t a[n_] := Mod[RamanujanTau[n], 2197]; Array[a, 100] (* _Amiram Eldar_, Jan 05 2025 *)

%o (PARI) a(n) = ramanujantau(n) % 2197; \\ _Amiram Eldar_, Jan 05 2025

%Y Cf. A000594, A126842 (mod 13^1), A126843 (mod 13^2), this sequence (mod 13^3).

%K nonn

%O 1,2

%A _N. J. A. Sloane_, Feb 25 2007