A080702 - OEIS

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A080702

a(1)=3; for n>1, a(n) = smallest number > a(n-1) such that the condition "if n is in the sequence then a(n) is even" is satisfied.

3, 4, 6, 8, 9, 10, 11, 12, 14, 16, 18, 20, 21, 22, 23, 24, 25, 26, 27, 28, 30, 32, 34, 36, 38, 40, 42, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102

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

OFFSET

1,1

REFERENCES

Hsien-Kuei Hwang, S Janson, TH Tsai, Exact and asymptotic solutions of the recurrence f(n) = f(floor(n/2)) + f(ceiling(n/2)) + g(n): theory and applications, Preprint, 2016; http://140.109.74.92/hk/wp-content/files/2016/12/aat-hhrr-1.pdf. Also Exact and Asymptotic Solutions of a Divide-and-Conquer Recurrence Dividing at Half: Theory and Applications, ACM Transactions on Algorithms, 13:4 (2017), #47; DOI: 10.1145/3127585

LINKS

Table of n, a(n) for n=1..70.

FORMULA

{a(a(n))} = {2i : i >= 3}.

PROG

(PARI) lista(nn) = {v = vector(nn); v[1] = 3; prev = v[1]; for (n=2, nn, new = prev+1; if (vecsearch(vecsort(v, , 8), n) && (new % 2), new ++); v[n] = new; prev = new; ); v; } \\ Michel Marcus, Feb 16 2015

CROSSREFS

Equals A079945(n+1) - 1.

Sequence in context: A377431 A325209 A121543 * A156167 A376560 A090864

Adjacent sequences: A080699 A080700 A080701 * A080703 A080704 A080705

KEYWORD

nonn,easy

AUTHOR

Benoit Cloitre, Mar 01 2003

EXTENSIONS

More terms from Matthew Vandermast, Mar 05 2003

STATUS

approved