A187185 Parse the infinite string 0123456012345601234560... into distinct phrases 0, 1, 2, 3, 4, 5, 6, 01, 23, 45, 60, 12, 34, 56, 012, ...; a(n) = length of n-th phrase.
1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 7, 8, 7, 8, 7, 8, 7, 8, 7, 8, 7, 8, 7, 8, 9, 9, 9, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10, 10, 11, 11, 11, 11, 11, 11, 11, 12, 12, 12, 12, 12, 12, 12, 13, 13, 13, 13, 13, 13, 13, 14, 15, 14, 15, 14, 15, 14, 15, 14, 15, 14, 15, 14, 15, 16, 16, 16, 16, 16, 16, 16, 17, 17, 17, 17, 17, 17, 17, 18
Offset: 1
Links
- Ray Chandler, Table of n, a(n) for n = 1..1000
- Index entries for linear recurrences with constant coefficients, signature (1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1).
Programs
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Mathematica
Join[{1, 1, 1, 1, 1, 1},LinearRecurrence[{1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1},{1, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 7, 8, 7, 8, 7, 8, 7, 8, 7, 8, 7, 8, 7, 8},114]] (* Ray Chandler, Aug 26 2015 *) -
PARI
Vec(x*(1 + x^7 + x^14 + x^21 + x^28 + x^35 + x^42 + x^43 - x^44 + x^45 - x^46 + x^47 - x^48 - x^50 + x^51 - x^52 + x^53 - x^54 + x^55) / ((1 - x)^2*(1 + x + x^2 + x^3 + x^4 + x^5 + x^6)*(1 + x^7 + x^14 + x^21 + x^28 + x^35 + x^42)) + O(x^80)) \\ Colin Barker, Jan 31 2020
Formula
After the initial block of seven 1's, the sequence is quasi-periodic with period 49, increasing by 7 after each block.
From Colin Barker, Jan 31 2020: (Start)
G.f.: x*(1 + x^7 + x^14 + x^21 + x^28 + x^35 + x^42 + x^43 - x^44 + x^45 - x^46 + x^47 - x^48 - x^50 + x^51 - x^52 + x^53 - x^54 + x^55) / ((1 - x)^2*(1 + x + x^2 + x^3 + x^4 + x^5 + x^6)*(1 + x^7 + x^14 + x^21 + x^28 + x^35 + x^42)).
a(n) = a(n-1) + a(n-49) - a(n-50) for n>56.
(End)
Comments