A138374 -id:A138374 - cp's OEIS frontend

A138373 Count of post-period decimal digits up to which the rounded n-th convergent to sqrt(5)/2 agrees with the exact value.

1, 3, 3, 5, 6, 8, 9, 10, 9, 13, 13, 15, 15, 18, 19, 20, 22, 22, 24, 25, 26, 27, 29, 30, 32, 33, 34, 35, 36, 38, 39, 40, 41, 43, 44, 45, 47, 47, 49, 50, 52, 53, 54, 55, 56, 58, 57, 60, 61, 62, 64, 64, 67, 68, 68, 71, 72, 73, 74, 75, 76, 78, 78, 80, 82, 83, 84, 85, 86, 88, 88, 90

Offset: 1

Artur Jasinski, Mar 17 2008

Defined equivalent to A138367 considering the constant 1.1188.. = 10*A020837 and its convergents 9/8 (n=1), 19/17 (n=2), 161/144 (n=3), 341/305 (n=4), 2889/2584 (n=5).

Cf. A138335 - A138339, A138343, A138366, A138367, A138369, A138370 - A138374.

Definition and values replaced as defined via continued fractions - R. J. Mathar, Oct 01 2009

A138372 Count of post-period decimal digits up to which the rounded n-th convergent to A103814 agrees with the exact value.

Original entry on oeis.org

1, 3, 3, 4, 3, 4, 5, 6, 6, 7, 8, 8, 9, 10, 11, 12, 13, 13, 14, 16, 16, 18, 21, 23, 23, 24, 26, 27, 27, 29, 29, 30, 30, 31, 32, 34, 37, 36, 39, 40, 41, 42, 43, 43, 46, 47, 48, 48, 49, 50, 50, 52, 53, 54, 55, 56, 56, 58, 58, 59, 62, 63, 65, 66, 67, 68, 69, 70, 70, 71, 73, 73, 75

Offset: 1

Artur Jasinski, Mar 17 2008

This is a measure of the quality of the n-th convergent to the Pentanacci constant A103814 if the convergent and the exact value are compared rounded to an increasing number of digits. The sequence of rounded values of A103814 is 2, 2.0, 1.97, 1.966, 1.9659, 1.96595, 1.965948, 1.9659482 etc. The n-th convergents are 2 (n=1), 57/29 (n=2), 116/59 (n=3), 173/88 (n=4), 462/235 (n=5) etc, each with associated rounded decimal expansions.

a(n) is the maximum number of post-period digits of the two expansions if compared at the same level of rounding.

			For n=5, the 5th convergent is 462/235 = 1.96595744.., with a sequence of rounded representations 2, 2.0, 1.97, 1.966, 1.9660, 1.96596, etc.
Rounded to 1, 2, or 3 post-period decimal digits, this is the same as the rounded version of the exact value, but disagrees if both are rounded to 4 decimal digits, where 1.9659 <> 1.9660.
So a(5) = 3 (digits), the maximum rounding level with agreement.

Cf. A138335 - A138339, A138343, A138366, A138367, A138369 - A138371, A138373 - A138374.

Definition and values replaced as defined via continued fractions - R. J. Mathar, Oct 01 2009

cp's OEIS Frontend

A138373 Count of post-period decimal digits up to which the rounded n-th convergent to sqrt(5)/2 agrees with the exact value.

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