1,1

Sequence appears to include all numbers m such that 8^5 is the highest power of 2 dividingA005148(m). General conjecture: numbers k such that 8^j is the highest power of 2 dividingA005148(k) is the same sequence as numbers having exactly (j+1) 1's in their binary representation. -Benoit Cloitre,Jun 22 2002

Ivan Neretin,Table of n, a(n) for n = 1..10000

Robert Baillie,Summing the curious series of Kempner and Irwin,arXiv:0806.4410 [math.CA], 2008-2015. See p. 18 for Mathematica code irwinSums.m.

a(n+1) =A057168(a(n)). -M. F. Hasler,Aug 27 2014

Sum_{n>=1} 1/a(n) = 1.387753111935705074750004158584017188750706394077047633137401652680870607884... (calculated using Baillie's irwinSums.m, see Links). -Amiram Eldar,Feb 14 2022

Select[ Range[ 63, 380 ], (Count[ IntegerDigits[ #, 2 ], 1 ]==6)& ]

(PARI) is_A023688(n)=hammingweight(n)==6 \\M. F. Hasler,Aug 27 2014

(PARI) print1(t=2^6-1); for(i=2, 50, print1( "," t=A057168(t))) \\M. F. Hasler,Aug 27 2014

Cf.A000079,A018900,A014311,A014312,A014313,A023689,A023690,A023691(Hamming weight = 1..9).

Cf.A005148,A057168.

Sequence in context:A343003A253021A039480*A118157A257897A261108

Adjacent sequences:A023685A023686A023687*A023689A023690A023691

nonn,base,easy

approved