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 A084054 5*n digit-reversed mod 5. 6
 1, 1, 2, 2, 3, 3, 4, 4, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 0, 0, 0, 0, 0, 0, 0 (list; graph; refs; listen; history; text; internal format)
 OFFSET 2,3 COMMENTS The pattern of increasing frequency of repetition of digits is clear. LINKS FORMULA Contribution from Enrique Pérez Herrero, Jun 14 2010: (Start) a(n)=mod(floor(5*n/10^(floor(log_10(5*n)))),5), this formula comes from the modulus 5 of the first digit of 5*n. a(10^n)=1 (End) EXAMPLE a(61) =3 as, 61*5 = 305,digit reversed = 503 ==3 (mod 5) MATHEMATICA Contribution from Enrique Pérez Herrero, Jun 14 2010: (Start) A084054[n_Integer]:=Mod[FromDigits[Reverse[IntegerDigits[5*n]]], 5]; (* Alternative formula *) A084054[n_Integer]:=Mod[Floor[5*n/10^Floor[Log[10, 5*n]]], 5] (End) CROSSREFS Cf. A084052, A084053, A084055, A084339, A084340, A084341. Sequence in context: A117171 A325356 A304706 * A106747 A083447 A252489 Adjacent sequences:  A084051 A084052 A084053 * A084055 A084056 A084057 KEYWORD base,easy,nonn AUTHOR Amarnath Murthy and Meenakshi Srikanth (menakan_s(AT)yahoo.com), May 26 2003 EXTENSIONS More terms from Ray Chandler, May 27 2003 STATUS approved

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Last modified March 28 05:38 EDT 2020. Contains 333073 sequences. (Running on oeis4.)