A364291 - OEIS

A364291

Numbers k such that A243071(k) <= k.

1, 2, 3, 4, 6, 8, 9, 12, 15, 16, 18, 24, 25, 27, 30, 32, 35, 36, 45, 48, 49, 50, 54, 60, 63, 64, 70, 72, 75, 77, 81, 90, 96, 98, 100, 105, 108, 120, 121, 125, 126, 128, 135, 140, 143, 144, 147, 150, 154, 162, 165, 169, 175, 180, 189, 192, 196, 200, 210, 216, 225, 231, 240, 242, 243, 245, 250, 252, 256, 270, 273

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

If k is present, then 2*k is also present, and vice versa.

LINKS

Table of n, a(n) for n=1..71.

PROG

(PARI)

A064989(n) = { my(f=factor(n>>valuation(n, 2))); for(i=1, #f~, f[i, 1] = precprime(f[i, 1]-1)); factorback(f); };

A243071(n) = if(n<=2, n-1, if(!(n%2), 2*A243071(n/2), 1+(2*A243071(A064989(n)))));

isA364291(n) = (A243071(n)<=n);