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A109593 Sequence and first differences include all odd numbers exactly once. 1
1, 4, 9, 16, 27, 40, 55, 72, 91, 112, 135, 160, 189, 220, 253, 288, 325, 364, 405, 448, 493, 540, 589, 640, 693, 750, 809, 870, 933, 998, 1065, 1134, 1205, 1278, 1353, 1430, 1509, 1590, 1673, 1758, 1845, 1934, 2027, 2122, 2219, 2318, 2419, 2522, 2627, 2734 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
See A005228.
LINKS
FORMULA
a(n) = n^2 + C*n^(3/2) + O(n), where C = 5/6. According to the simplified model: the sum of n consecutive odd numbers without the odd squares. - Thomas Ordowski, Sep 24 2014
MATHEMATICA
a = {1}; d = 3; k = 1; Do[ While[ Position[a, d] != {}, d += 2 ]; k = k + d; d += 2; a = Append[a, k], {n, 49} ]; a (* Robert G. Wilson v, Sep 28 2005 *)
CROSSREFS
Cf. A005228.
Sequence in context: A195618 A066969 A213495 * A237589 A138981 A138993
KEYWORD
base,easy,nonn
AUTHOR
Eric Angelini, Aug 30 2005
EXTENSIONS
Corrected and extended by Robert G. Wilson v, Sep 28 2005
STATUS
approved

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Last modified June 24 22:33 EDT 2024. Contains 373690 sequences. (Running on oeis4.)