A332183 a(n) = 8*(10^(2n+1)-1)/9 - 5*10^n.

3, 838, 88388, 8883888, 888838888, 88888388888, 8888883888888, 888888838888888, 88888888388888888, 8888888883888888888, 888888888838888888888, 88888888888388888888888, 8888888888883888888888888, 888888888888838888888888888, 88888888888888388888888888888, 8888888888888883888888888888888

Offset

0,1

Links

Table of n, a(n) for n=0..15.

Index entries for linear recurrences with constant coefficients, signature (111,-1110,1000).

Formula

a(n) = 8*A138148(n) + 3*10^n = A002282(2n+1) - 5*10^n.

G.f.: (3 + 505*x - 1300*x^2)/((1 - x)(1 - 10*x)(1 - 100*x)).

a(n) = 111*a(n-1) - 1110*a(n-2) + 1000*a(n-3) for n > 2.

Maple

A332183 := n -> 8*(10^(2*n+1)-1)/9-5*10^n;

Mathematica

Array[8 (10^(2 # + 1)-1)/9 - 5*10^# &, 15, 0]

Prog

(PARI) apply( {A332183(n)=10^(n*2+1)\9*8-5*10^n}, [0..15])
(Python) def A332183(n): return 10**(n*2+1)//9*8-5*10**n

Crossrefs

Cf. A002275 (repunits R_n = (10^n-1)/9), A002282 (8*R_n), A011557 (10^n).

Cf. A138148 (cyclops numbers with binary digits only).

Cf. A332113 .. A332193 (variants with different repeated digit 1, ..., 9).

Cf. A332180 .. A332189 (variants with different middle digit 0, ..., 9).

Sequence in context: A096086 A062658 A266654 * A000723 A020525 A252762

Adjacent sequences: A332180 A332181 A332182 * A332184 A332185 A332186

Keyword

nonn,base,easy

Author

M. F. Hasler, Feb 08 2020

Status

approved