cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A233388 Odious numbers that are the sum of 2 consecutive odious numbers.

Original entry on oeis.org

11, 19, 35, 47, 59, 67, 79, 91, 107, 115, 131, 143, 155, 171, 179, 191, 203, 211, 227, 239, 251, 259, 271, 283, 299, 307, 319, 331, 339, 355, 367, 379, 395, 403, 419, 431, 443, 451, 463, 475, 491, 499, 515, 527, 539, 555, 563, 575, 587, 595
Offset: 1

Views

Author

Gerasimov Sergey, Dec 08 2013

Keywords

Comments

Composites in this sequence: 35, 91, 115, 143, 155, 171, 203, 259, 299, 319, 229, 366, 395, 403, 451, 475, 515, 527, 539, 555, 575, 595,...
(a(n + 1) - a(n))/4 are 2, 4, 3, 3, 2, 3, 3, 4, 2, 4, 3, 3, 4, 2, 3, 3, 2, 4, 3, 3, 2, 3, 3, 4, 2, 3, 3, 2, 4, 3, 3, 4, 2, 4, 3, 3, 2, 3,...

Examples

			11 is in this sequence because 11 = A000069(6) and 11 = 4 + 7 where 4 = A000069(3) and 7 = A000069(4).
19 is in this sequence because 19 = A000069(10) and 19 = 8 + 11 where 8 = A000069(5) and 11 = A000069(6).

Links

Crossrefs

Cf. A000069, A227930, A131323, A234431.

Programs

  • Mathematica
    odQ[n_] := OddQ @ DigitCount[n, 2, 1]; Select[Plus @@@ Partition[Select[Range[300] , odQ], 2, 1], odQ] (* Amiram Eldar, Aug 29 2020 *)

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

Original entry on oeis.org

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

Views

Author

Gerasimov Sergey, Dec 27 2013

Keywords

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

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.

Programs

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

Extensions

Terms recomputed and checked by Antti Karttunen, Dec 29 2013
Showing 1-2 of 2 results.

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