A352205 a(0) = 0; for n>0, a(n) is the index of the last term in A109812 that is <= 2^n - 1.

0, 1, 4, 16, 28, 76, 162, 418, 650, 1892, 3555, 7252, 20059, 39786, 84653, 174566, 343911, 690189, 1688099, 3366971, 7131089, 14446268, 31036955, 62485240, 145444358, 290692248, 624275567

Offset: 0

Author

N. J. A. Sloane and Chai Wah Wu, Mar 29 2022

Keywords

• nonn
• base
• more

Comments

It appears that the last term in A109812 of binary length n is always 2^n - 1 itself. The term after that is (by definition) A352206(n).

If we subtract 1 from a(n), we appear to get a subsequence of A352204, the indices of record high points in A109812.

There are also occasional near-coincidences with A305370.

Examples

			The last term in A109812 of binary length at most 3 is A109812(16) = 7, so a(3) = 16.
		

Crossrefs

Cf. A109812, A305370, A352203, A352204, A352206.

Extensions

a(18)-a(26) from Walter Trump, Apr 26 2022