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A126832 Ramanujan numbers (A000594) read mod 5. 6
1, 1, 2, 3, 0, 2, 1, 0, 2, 0, 2, 1, 2, 1, 0, 1, 1, 2, 0, 0, 2, 2, 2, 0, 0, 2, 0, 3, 0, 0, 2, 1, 4, 1, 0, 1, 1, 0, 4, 0, 2, 2, 2, 1, 0, 2, 1, 2, 3, 0, 2, 1, 2, 0, 0, 0, 0, 0, 0, 0, 2, 2, 2, 3, 0, 4, 1, 3, 4, 0, 2, 0, 2, 1, 0, 0, 2, 4, 0, 0, 1, 2, 2, 1, 0, 2, 0, 0, 0, 0, 2, 1, 4, 1, 0, 2, 1, 3, 4, 0, 2, 2, 2, 0, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

REFERENCES

G. H. Hardy, Ramanujan: twelve lectures on subjects suggested by his life and work, AMS Chelsea Publishing, Providence, Rhode Island, 2002, pp. 166-167.

LINKS

Seiichi Manyama, Table of n, a(n) for n = 1..10000

R. P. Bambah and S. Chowla, Congruence properties of Ramanujan’s function tau(n), Bull. Amer. Math. Soc. 53 (1947), 950-955.

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*sigma(n) mod 5. - Michel Marcus, Apr 26 2016. See also the Hardy reference, p. 166, (10.5.2), with a proof. - Wolfdieter Lang, Feb 03 2017

MATHEMATICA

Mod[RamanujanTau@ #, 5] & /@ Range@ 105 (* Michael De Vlieger, Apr 26 2016 *)

CROSSREFS

Cf. A000594, A064987.

Cf. this sequence (mod 5^1), A126833 (mod 5^2), A126834 (mod 5^3), A126835 (mod 5^4).

Sequence in context: A059066 A059067 A065861 * A068908 A226192 A113407

Adjacent sequences:  A126829 A126830 A126831 * A126833 A126834 A126835

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Feb 25 2007

STATUS

approved

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Last modified August 20 15:27 EDT 2017. Contains 290835 sequences.