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%I #2 Mar 30 2012 17:30:37
%S 1,3,6,11,17,24,33,43,54,66,79,94,110,127,145,164,184,206,229,253,278,
%T 304,331,359,389,420,452,485,519,554,590,627,665,705,746,788,831,875,
%U 920,966,1013,1061,1110,1161,1213,1266,1320,1375,1431,1488,1546,1605
%N a(n+1) = a(n) + n + the number of a(k)'s <= n, 1 <= k <= n and a(1) = 1.
%e a(7) = a(6) + 6 + the number of a(k)'s <= 6 = 24 + 6 + 3 ( a(3) is <= 6) = 33.
%t f[1] = 1; f[n_] := f[n] = Block[ {k = 1}, While[ f[k] < n, k++ ]; k--; Return[ f[n - 1] + (n - 1) + k]]; Table[ f[n], {n, 1, 60} ]
%K nonn
%O 1,2
%A _Robert G. Wilson v_, Nov 25 2001
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