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%I #13 Jun 11 2022 11:43:42
%S 2,3,3,3,6,18,63,273,1386,7938,50523,353793,2702766,22368258,
%T 199360983,1903757313,19391512146,209865342978,2404879675443,
%U 29088885112833,370371188237526,4951498053124098,69348874393137903,1015423886506852353
%N a(n) = A000111(n) + A014695(n).
%C a(n) is a multiple of 3 for n > 0.
%p A000111 := proc(n) local x; n!*coeftayl( sec(x)+tan(x),x=0,n) ; end: A014695 := proc(n) local x; coeftayl( (1+2*x+2*x^2+x^3)/(1-x^4),x=0,n) ; end: A141479 := proc(n) A000111(n)+A014695(n) ; end: for n from 0 to 30 do printf("%a,",A141479(n)) ; od; # _R. J. Mathar_, Sep 12 2008
%o (Python)
%o from itertools import count, islice, accumulate
%o def A141479_gen(): # generator of terms
%o yield from (2,3)
%o blist = (0,1)
%o for n in count(0):
%o yield (blist := tuple(accumulate(reversed(blist),initial=0)))[-1] + (2,1,1,2)[n & 3]
%o A141479_list = list(islice(A141479_gen(),40)) # _Chai Wah Wu_, Jun 09-11 2022
%K nonn,easy
%O 0,1
%A _Paul Curtz_, Aug 09 2008
%E Extended by _R. J. Mathar_, Sep 12 2008