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A152919 Simple switched sequence: a(n)= If[n == 1, 1, If[Mod[n, 2] == 0, n^2/4 + n/2, n^2/4 + n - 5/4]]. 0
1, 2, 4, 6, 10, 12, 18, 20, 28, 30, 40, 42, 54, 56, 70, 72, 88, 90, 108, 110, 130, 132, 154, 156, 180, 182, 208, 210, 238, 240, 270, 272, 304, 306, 340, 342, 378, 380, 418, 420, 460, 462, 504, 506, 550, 552, 598, 600, 648, 650, 700, 702, 754, 756, 810, 812, 868 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..57.

FORMULA

a(n)= If[n == 1, 1, If[Mod[n, 2] == 0, n^2/4 + n/2, n^2/4 + n - 5/4]].

MATHEMATICA

Clear[a, n]; a[n_] := If[n == 1, 1, If[Mod[n, 2] == 0, n^2/4 + n/2, n^2/4 + n - 5/4]];

Table[a[n], {n, 1, 100}]

CROSSREFS

Sequence in context: A167856 A293750 A162578 * A306564 A002088 A092249

Adjacent sequences:  A152916 A152917 A152918 * A152920 A152921 A152922

KEYWORD

nonn

AUTHOR

Roger L. Bagula, Dec 15 2008

STATUS

approved

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Last modified October 13 18:14 EDT 2019. Contains 327981 sequences. (Running on oeis4.)