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%I #11 Feb 23 2020 15:31:32
%S 1,2,4,8,10,11,13,17,19,20,22,26,28,29,31,35,37,38,40,44,46,47,49,53,
%T 55,56,58,62,64,65,67,71,73,74,76,80,82,83,85,89,91,92,94,98,100,101,
%U 103,107,109,110,112,116,118,119,121,125,127,128,130,134,136,137,139,143,145,146,148,152,154,155
%N Iterated sum of digits of n is a power of 2.
%F Conjectures from _Colin Barker_, Feb 10 2020: (Start)
%F G.f.: x*(1 + x + 2*x^2 + 4*x^3 + x^4) / ((1 - x)^2*(1 + x)*(1 + x^2)).
%F a(n) = a(n-1) + a(n-4) - a(n-5) for n>5.
%F (End)
%F This g.f. follows from the observation that a(n+4) = a(n)+9 and this holds since the iterated sum of digits of N equals the iterated sum of digits of N+9. - _Peter Bala_, Feb 10 2020
%Y Cf. A010888, A028838, A028889.
%K nonn,base
%O 1,2
%A _N. J. A. Sloane_.
%E More terms from Scott Lindhurst (ScottL(AT)alumni.princeton.edu)
%E Checked by Neven Juric (neven.juric(AT)apis-it.hr), Feb 04 2008
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