login
a(1)=1; a(2)=4. a(n) = a(n-1) + (n-th positive integer which does not occur in sequence A131938).
4

%I #9 Apr 09 2014 10:15:19

%S 1,4,8,14,21,29,38,49,61,74,88,103,120,138,157,177,198,220,244,269,

%T 295,322,350,379,409,440,473,507,542,578,615,653,692,732,773,816,860,

%U 905,951,998,1046,1095,1145,1196,1248,1302,1357,1413,1470,1528,1587,1647

%N a(1)=1; a(2)=4. a(n) = a(n-1) + (n-th positive integer which does not occur in sequence A131938).

%e A131938: 2,5,10,16,23,32,42,53,...

%e Positive integers not in A131938: 1,3,4,6,7,8,9,11,...

%e So A131937(8) = A131937(7) + 11 = 49.

%Y Cf. A131938.

%K nonn

%O 1,2

%A _Leroy Quet_, Jul 30 2007

%E More terms from _Farideh Firoozbakht_, Aug 07 2007

%E a(51)-a(52) from _Ray Chandler_, Mar 06 2010