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A255176 a(n) = H_n(2,2) where H_n is the n-th hyperoperator. 4
3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

See A054871 for definitions and key links.

Also, decimal expansion of 31/90. - Bruno Berselli, Mar 18 2015

Essentially the same as A010709, A040002, A113311, A123932, and A151798. - R. J. Mathar, Mar 20 2015

Remainder of the Euclidean division when 10^(10^n) is divided by 7 (proof by induction for n >= 1) [see reference Julien Freslon & Jérôme Poineau]; example: 10^(10^1) = 1428571428 * 7 + 4. - Bernard Schott, Aug 28 2020

REFERENCES

Julien Freslon & Jérôme Poineau, Les 100 exercices-types de mathématiques: MPSI/PCSI/PTSI, EdiScience, 2007, Exercice 11.2, page 242.

LINKS

Table of n, a(n) for n=0..104.

Wikipedia, Hyperoperation.

Index entries for linear recurrences with constant coefficients, signature (1).

FORMULA

G.f.: (3 + x)/(1 - x). - Bruno Berselli, Mar 18 2015

a(n) = 10^(10^n) mod 7. - Bernard Schott, Aug 28 2020

EXAMPLE

a(0) = H_0(2,2) = 2+1 = 3.

a(1) = H_1(2,2) = 2+2 = 4.

a(2) = H_2(2,2) = 2*2 = 4.

a(3) = H_3(2,2) = 2^2 = 4.

a(n) = H_n(2,2) = H_{n-1}(2,H_n(2,1)) = H_{n-1}(2,2) = 4, for n>1.

CROSSREFS

Cf. A054871.

Cf. A040000, A157532.

Sequence in context: A280356 A018244 A113311 * A288177 A349992 A064042

Adjacent sequences:  A255173 A255174 A255175 * A255177 A255178 A255179

KEYWORD

nonn,easy,cons

AUTHOR

Natan Arie Consigli, Feb 25 2015

EXTENSIONS

Edited by Danny Rorabaugh, Oct 20 2015

STATUS

approved

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Last modified September 26 20:57 EDT 2022. Contains 357050 sequences. (Running on oeis4.)