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A131937
a(1)=1; a(2)=4. a(n) = a(n-1) + (n-th positive integer which does not occur in sequence A131938).
4
1, 4, 8, 14, 21, 29, 38, 49, 61, 74, 88, 103, 120, 138, 157, 177, 198, 220, 244, 269, 295, 322, 350, 379, 409, 440, 473, 507, 542, 578, 615, 653, 692, 732, 773, 816, 860, 905, 951, 998, 1046, 1095, 1145, 1196, 1248, 1302, 1357, 1413, 1470, 1528, 1587, 1647
OFFSET
1,2
EXAMPLE
A131938: 2,5,10,16,23,32,42,53,...
Positive integers not in A131938: 1,3,4,6,7,8,9,11,...
So A131937(8) = A131937(7) + 11 = 49.
CROSSREFS
Cf. A131938.
Sequence in context: A312697 A312698 A312699 * A183857 A088804 A374505
KEYWORD
nonn
AUTHOR
Leroy Quet, Jul 30 2007
EXTENSIONS
More terms from Farideh Firoozbakht, Aug 07 2007
a(51)-a(52) from Ray Chandler, Mar 06 2010
STATUS
approved