

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
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OFFSET

1,2


COMMENTS

See A005228.


LINKS

Alois P. Heinz, Table of n, a(n) for n = 1..1000


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
Adjacent sequences: A109590 A109591 A109592 * A109594 A109595 A109596


KEYWORD

base,easy,nonn


AUTHOR

Eric Angelini, Aug 30 2005


EXTENSIONS

Corrected and extended by Robert G. Wilson v, Sep 28 2005


STATUS

approved



