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A294456
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a(1)=0, a(2)=1; thereafter a(n) = a(floor(n/2)) + a(ceiling(n/2)) + 2.
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2
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0, 1, 3, 4, 6, 8, 9, 10, 12, 14, 16, 18, 19, 20, 21, 22, 24, 26, 28, 30, 32, 34, 36, 38, 39, 40, 41, 42, 43, 44, 45, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 96, 98, 100, 102, 104, 106, 108, 110, 112, 114, 116
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OFFSET
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1,3
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LINKS
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FORMULA
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G.f. g(x) satisfies g(x) = (x^2+x^3)/(1-x) + (x + 2 + 1/x)*g(x^2). - Robert Israel, Nov 26 2017
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MAPLE
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f:= proc(n) option remember;
procname(floor(n/2)) + procname(ceil(n/2))+2 end proc:
f(1):= 0: f(2):= 1:
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PROG
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(PARI) first(n) = { my(res = vector(n)); res[1] = 0; res[2] = 1; for(i = 3, n, res[i] = res[floor(i/2)] + res[ceil(i/2)] + 2); res; } \\ Iain Fox, Nov 26 2017
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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