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 A126825 Ramanujan numbers (A000594) read mod 3. 2
 1, 0, 0, 1, 0, 0, 2, 0, 0, 0, 0, 0, 2, 0, 0, 1, 0, 0, 2, 0, 0, 0, 0, 0, 1, 0, 0, 2, 0, 0, 2, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 1, 0, 0, 2, 0, 0, 0, 0, 0, 2, 0, 0, 2, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 2, 0, 0, 1, 0, 0, 2, 0, 0 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,7 COMMENTS a(4*n) = a(n) (see Corollary 2.2. p. 726 of Ewell link). - Michel Marcus, Dec 23 2012 LINKS Table of n, a(n) for n=1..105. R. P. Bambah and S. Chowla, Congruence properties of Ramanujan’s function tau(n), Bull. Amer. Math. Soc. 53 (1947), 950-955. John A. Ewell, New representations of Ramanujan's tau function, Proc. Amer. Math. Soc. 128 (2000), 723-726 H. P. F. Swinnerton-Dyer, On l-adic representations and congruences for coefficients of modular forms, pp. 1-55 of Modular Functions of One Variable III (Antwerp 1972), Lect. Notes Math., 350, 1973. FORMULA a(n) = sigma(n) mod 3, for n coprime to 3. - Michel Marcus, Apr 26 2016 MAPLE seq(modp(numtheory:-sigma(n), 3)*(1-abs(mods(n-1, 3))), n=1..105); # Peter Luschny, Apr 26 2016 MATHEMATICA Mod[RamanujanTau@ #, 3] & /@ Range@ 105 (* Michael De Vlieger, Apr 26 2016 *) CROSSREFS Cf. A000594, A000203. Sequence in context: A045837 A319687 A374217 * A045833 A117896 A356735 Adjacent sequences: A126822 A126823 A126824 * A126826 A126827 A126828 KEYWORD nonn AUTHOR N. J. A. Sloane, Feb 25 2007 STATUS approved

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Last modified July 17 23:53 EDT 2024. Contains 374377 sequences. (Running on oeis4.)