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A298171
Decimal expansion of ratio-sum for A296776; see Comments.
3
5, 6, 1, 1, 5, 6, 2, 0, 5, 7, 6, 5, 6, 2, 2, 5, 4, 7, 7, 0, 3, 2, 4, 4, 3, 4, 5, 6, 0, 9, 2, 5, 7, 9, 4, 8, 0, 9, 8, 2, 7, 0, 9, 5, 8, 6, 5, 5, 5, 5, 7, 3, 7, 0, 6, 5, 0, 1, 9, 0, 5, 7, 3, 9, 5, 3, 5, 1, 0, 5, 4, 3, 3, 1, 7, 6, 6, 7, 6, 0, 2, 0, 1, 0, 5, 4
OFFSET
1,1
COMMENTS
Suppose that A = (a(n)), for n >= 0, is a sequence, and g is a real number such that a(n)/a(n-1) -> g. The ratio-sum for A is |a(1)/a(0) - g| + |a(2)/a(1) - g| + ..., assuming that this series converges. For A = A298171, we have g = (1 + sqrt(5))/2, the golden ratio (A001622). See the guide at A296462 for related sequences.
EXAMPLE
ratio-sum = 5.611562057656225477032443456092579480982...
MATHEMATICA
a[0] = 1; a[1] = 3; b[0] = 2; b[1] = 4; b[2] = 5;
a[n_] := a[n] = a[n - 1] + a[n - 2] + b[n] + 2 n;
j = 1; While[j < 16, k = a[j] - j - 1;
While[k < a[j + 1] - j + 1, b[k] = j + k + 2; k++]; j++];
u =Table[a[n], {n, 0, k}]; (* A296776 *)
g = GoldenRatio; s = N[Sum[- g + a[n]/a[n - 1], {n, 1, 1000}], 200]
Take[RealDigits[s, 10][[1]], 100] (* A298171 *)
CROSSREFS
KEYWORD
nonn,easy,cons
AUTHOR
Clark Kimberling, Feb 09 2018
STATUS
approved