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A045957
Twin even-lucky-numbers: middle terms.
4
3, 5, 11, 19, 21, 35, 43, 51, 53, 69, 99, 101, 115, 117, 131, 139, 149, 171, 197, 213, 229, 245, 261, 299, 309, 325, 373, 387, 389, 419, 435, 437, 517, 523, 533, 547, 587, 597, 629, 643, 645, 707, 709, 715, 739, 741, 779, 869, 883, 885, 915, 963, 965, 995, 997, 1091
OFFSET
1,1
COMMENTS
Numbers k such that both k-1 and k+1 are even-lucky numbers (A045954). - Amiram Eldar, Mar 20 2024
LINKS
FORMULA
a(n) = A045955(n) + 1 = A045956(n) - 1. - Amiram Eldar, Mar 20 2024
MATHEMATICA
evenLuckies[max_] := Module[{lst = Range[2, max, 2], i = 2, len}, While[i <= (len = Length@lst) && (k = lst[[i]]) <= len, lst = Drop[lst, {k, len, k}]; i++]; lst]; twinMid[max_] := Module[{s = evenLuckies[max]}, s[[Position[ Differences[s], 2] // Flatten]] + 1]; twinMid[1100] (* Amiram Eldar, Mar 20 2024, after Robert G. Wilson v at A045954 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved