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A164854
Diagonal sum of generalized Pascal triangle; (10^n,1).
1
1, 1, 11, 12, 113, 125, 1138, 1263, 11401, 12664, 114065, 126729, 1140794, 1267523, 11408317, 12675840, 114084157, 126759997, 1140844154, 1267604151, 11408448305, 12676052456, 114084500761, 126760553217, 1140845053978, 1267605607195, 11408450661173
OFFSET
0,3
FORMULA
From Robert Israel, Jul 01 2016: (Start)
G.f.: (1-x^2)/((1-10*x^2)*(1-x-x^2)).
a(n) = (171-9*(-1)^n)*10^floor(n/2)/142 + (A000045(n)-10*A000045(n+2))/71. (End)
a(n) = a(n-1)+11*a(n-2)-10*a(n-3)-10*a(n-4). - Wesley Ivan Hurt, Apr 21 2021
MAPLE
f:= gfun:-rectoproc({10*a(n-4)+10*a(n-3)-11*a(n-2)-a(n-1)+a(n),
a(0)=1, a(1)=1, a(2)=11, a(3)=12}, a(n), remember):
map(f, [$0..30]); # Robert Israel, Jul 01 2016
MATHEMATICA
LinearRecurrence[{1, 11, -10, -10}, {1, 1, 11, 12}, 30] (* Harvey P. Dale, Apr 07 2022 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Mark Dols, Aug 28 2009
EXTENSIONS
More terms from Harvey P. Dale, Apr 07 2022
STATUS
approved