A232228 - OEIS

A232228

a(1)=1; thereafter a(n) = 2^(number of bits in binary expansion of a(n-1)) + 1 + a(n-1).

1, 4, 13, 30, 63, 128, 385, 898, 1923, 3972, 8069, 16262, 32647, 65416, 130953, 262026, 524171, 1048460, 2097037, 4194190, 8388495, 16777104, 33554321, 67108754, 134217619, 268435348, 536870805, 1073741718, 2147483543, 4294967192, 8589934489, 17179869082, 34359738267, 68719476636

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OFFSET

1,2

COMMENTS

An infinite subsequence of A010061.

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1001

D. W. Bange, Solution to Problem E 2408, Amer. Math. Monthly, 81 (1974), 407.

Index entries for Colombian or self numbers and related sequences

MAPLE

f:=proc(n) option remember; if n=1 then 1 else 2^(nops(convert(f(n-1), base, 2)))+1+f(n-1); fi; end;

[seq(f(n), n=1..40)];