A126022 - OEIS

A126022

a(1)=1; for n>1, a(n) = a(n-1) + (the number of terms of {a(k)} which are <= n).

%I #11 Mar 05 2024 16:32:24

%S 1,2,4,7,10,13,17,21,25,30,35,40,46,52,58,64,71,78,85,92,100,108,116,

%T 124,133,142,151,160,169,179,189,199,209,219,230,241,252,263,274,286,

%U 298,310,322,334,346,359,372,385,398,411,424,438,452,466,480,494,508

%N a(1)=1; for n>1, a(n) = a(n-1) + (the number of terms of {a(k)} which are <= n).

%e There are four terms (1,2,4,7) of the sequence which are <= 9. So a(9) = a(8) + 4 = 25.

%t f[l_] := Block[{s = Length@l + 2}, Append[l, Last@l + Length@Select[l, # < s &]]]; Nest[f, {1}, 56] (* _Robert G. Wilson v_, Mar 01 2007 *)

%K easy,nonn

%O 1,2

%A _Leroy Quet_, Feb 27 2007

%E More terms from _Robert G. Wilson v_, Mar 01 2007