A006092 - OEIS

%I M0901 #31 Dec 28 2024 23:15:43

%S 2,3,10,12,13,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,

%T 38,39,200,201,202,203,204,205,206,207,208,209,210,211,212,213,214,

%U 215,216,217,218,219,220

%N Numbers beginning with letter 't' when spelled out in English.

%C The next 179 terms are all the numbers from 221 to 399. Assuming that '1000' is spelled 'one thousand', the following terms are the numbers in the intervals [x*1000 , x*1000+999] where x runs over all elements a(1),..,a(225) occurring up to there. Then the numbers in the intervals [x*10^6, (x+1)*10^6-1] appear, where x again runs over all preceding terms. _M. F. Hasler_, Mar 23 2011

%D Archimedeans Problems Drive, Eureka, 48 (1988), pages 55, 56, 99.

%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

%F Let g_k(x) = (x^(2k) - x^(4k) + x^(10k) - x^(11k) + x^(12k) - x^(14k) + x^(20k) - x^(40k) + x^(200k) - x^(400k))/(1-x). Then the g.f. of the characteristic function of this sequence is Sum_{j>=0} g_{1000^j}(x).

%K word,nonn

%O 1,1

%A _N. J. A. Sloane_.