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Increase the odd part of n to the next greater odd number.
2

%I #14 Mar 27 2022 13:38:06

%S 3,6,5,12,7,10,9,24,11,14,13,20,15,18,17,48,19,22,21,28,23,26,25,40,

%T 27,30,29,36,31,34,33,96,35,38,37,44,39,42,41,56,43,46,45,52,47,50,49,

%U 80,51,54,53,60,55,58,57,72,59,62,61,68,63,66,65,192,67,70,69

%N Increase the odd part of n to the next greater odd number.

%C This is +2 at the bit position of the odd part of n, that being the least significant 1-bit.

%C The least significant run of 1-bits changes from 0111..111 in n to 1000..001 in a(n).

%C Arrays A054582 and A135764 arrange terms into rows having the same number of trailing 0 bits. a(n) is the term to the right of n, i.e., next in its row.

%H Michael De Vlieger, <a href="/A349102/b349102.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) = n + A171977(n).

%F a(2*n) = 2*a(n).

%F a(2*n+1) = 2*n + 3.

%e n = 3448 = binary 1101 0111 1 000

%e a(n) = 3464 = binary 1101 1000 1 000

%t Array[# + 2^(IntegerExponent[#, 2] + 1) &, 67] (* _Michael De Vlieger_, Mar 27 2022 *)

%o (PARI) a(n) = n + 2<<valuation(n,2);

%Y Cf. A000265 (odd part), A171977 (2 at odd part), A285326.

%Y Arrays: A054582, A135764.

%K nonn,easy

%O 1,1

%A _Kevin Ryde_, Mar 26 2022