A234011 The sums of 2 consecutive odious numbers (A000069).

3, 6, 11, 15, 19, 24, 27, 30, 35, 40, 43, 47, 51, 54, 59, 63, 67, 72, 75, 79, 83, 86, 91, 96, 99, 102, 107, 111, 115, 120, 123, 126, 131, 136, 139, 143, 147, 150, 155, 160, 163, 166, 171, 175, 179, 184, 187, 191, 195, 198, 203, 207, 211, 216, 219, 222, 227, 232, 235, 239, 243, 246

Offset

1,1

Comments

The union of A131323(k) and (A225822(m)+(-1)^m).

All even numbers in this sequence are evil numbers (A001969).

It seems that A233388(n) = a(A091785(n)).

Links

Antti Karttunen, Table of n, a(n) for n = 1..8192

Formula

a(n) = A000069(n) + A000069(n + 1).

4n - 2 <= a(n) <= 4n. - Charles R Greathouse IV, Dec 29 2013

a(2n+1) = 8n + 3 = A017101(n). - Ralf Stephan, Dec 31 2013

Mathematica

Plus @@@ Partition[Select[Range[125], OddQ[DigitCount[#, 2][[1]]] &], 2, 1] (* Amiram Eldar, Jul 24 2023 *)

Prog

(PARI) a(n)=4*n-hammingweight(n-1)%2-hammingweight(n)%2 \\ Charles R Greathouse IV, Dec 29 2013
(Scheme) (define (A234011 n) (+ (A000069 n) (A000069 (+ n 1)))) ;; Antti Karttunen, Dec 29 2013

Crossrefs

Cf. A000069, A003159 (indices of odd numbers in A234011), A036554 (indices of even numbers in A234011), A131323 (odd sums of 2 successive odious or 2 successive evil numbers), A233388 (odious numbers in A234011), A234431 (sums of 2 consecutive evil numbers), A017101, A091785, A225822, A227930, A233388.

Sequence in context: A225521 A067278 A310100 * A368384 A113960 A287075

Adjacent sequences: A234008 A234009 A234010 * A234012 A234013 A234014

Keyword

nonn,easy,base

Author

Gerasimov Sergey, Dec 27 2013

Extensions

Terms recomputed and checked by Antti Karttunen, Dec 29 2013

Status

approved