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 A126826 Ramanujan numbers (A000594) read mod 9. 0
 1, 3, 0, 4, 6, 0, 5, 6, 0, 0, 3, 0, 8, 6, 0, 7, 0, 0, 2, 6, 0, 0, 6, 0, 7, 6, 0, 2, 3, 0, 8, 0, 0, 0, 3, 0, 2, 6, 0, 0, 6, 0, 5, 3, 0, 0, 3, 0, 3, 3, 0, 5, 0, 0, 0, 3, 0, 0, 6, 0, 5, 6, 0, 1, 3, 0, 8, 0, 0, 0, 0, 0, 2, 6, 0, 8, 6, 0, 5, 6, 0, 0, 3, 0, 0, 6, 0, 0, 0, 0, 4, 6, 0, 0, 3, 0, 5, 0, 0, 1, 3, 0, 8, 3, 0 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Table of n, a(n) for n=1..105. R. P. Bambah and S. Chowla, A new congruence property of Ramanujan’s function tau(n), Bull. Amer. Math. Soc. 53 (1947), 768-769. 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) = n^2*sigma(n) mod 9. - Michel Marcus, Apr 25 2016 MATHEMATICA Mod[RamanujanTau@ #, 9] &@ Range@ 120 (* Michael De Vlieger, Apr 25 2016 *) PROG (PARI) a(n) = n^2*sigma(n) % 9; \\ Michel Marcus, Apr 26 2016 CROSSREFS Cf. A000203, A000594. Sequence in context: A307383 A111486 A192878 * A231983 A231982 A198575 Adjacent sequences: A126823 A126824 A126825 * A126827 A126828 A126829 KEYWORD nonn AUTHOR N. J. A. Sloane, Feb 25 2007 STATUS approved

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Last modified July 22 15:21 EDT 2024. Contains 374512 sequences. (Running on oeis4.)