OFFSET
0,2
COMMENTS
"The first 68 elements of the sequence are [given], then the greedy algorithm is used." For this B2-sequence: "The reciprocal sum is at least 2.16086," greater than that of the Mian-Chowla sequence (A005282), which is at most 2.158533. - Danny Rorabaugh (with quotes by Rachel Lewis), Sep 29 2015
REFERENCES
Steven R. Finch, Mathematical Constants, Cambridge, 2003, pp. 163-166, with section 2.20.2, Mian-Chowla and B2-Sequences
LINKS
Danny Rorabaugh, Table of n, a(n) for n = 0..848 (corrected by Sean A. Irvine and Eric W. Weisstein)
Steven R. Finch, Erdos's Reciprocal Sum Constants [Broken link]
Steven R. Finch, Erdos's Reciprocal Sum Constants [From the Wayback machine]
Rachel Lewis, Mian-Chowla and B2 sequences, 1999. [Thanks to Steven Finch for providing this document. Included with permission. - N. J. A. Sloane, Jan 02 2020]
Eric Weisstein's World of Mathematics, B2 Sequence.
FORMULA
For n>67, a(n) is the least number such that all pairwise differences of distinct elements of {a(0), ..., a(n)} are distinct. - Danny Rorabaugh, Sep 29 2015
MATHEMATICA
With[{seed = {1, 2, 4, 8, 13, 21, 31, 45, 66, 81, 97, 123, 148, 182, 204, 252, 291, 324, 352, 415, 486, 540, 651, 706, 781, 864, 963, 1003, 1148, 1217, 1371, 1409, 1523, 1673, 1974, 2105, 2191, 2317, 2496, 2652, 2726, 2858, 3219, 3268, 3500, 3605, 3864, 3962, 4237, 4334, 4659, 4767, 5235, 5282, 5545, 5798, 6285, 6452, 6752, 7305, 7433, 7523, 8024, 8679, 9012, 9327, 9703, 10103}}, Nest[Function[s, Append[s, First[Complement[Range[Last[s] + 1, 2 Last[s]], Flatten[Outer[Subtract, Union[Flatten[Outer[Plus, s, s]]], s]]]]]], seed, 20]] (* Eric W. Weisstein, Oct 09 2026 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
a(34) corrected by Steven Finch in email with Danny Rorabaugh, Sep 29 2015
b-file corrected from n=68 by Eric W. Weisstein, Oct 09 2026
STATUS
approved