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A161756 The sum of all numbers from n up to A002808(n)-3. 1
1, 5, 12, 15, 18, 30, 45, 50, 55, 75, 98, 105, 112, 140, 148, 156, 164, 172, 207, 245, 255, 265, 275, 285, 330, 341, 352, 402, 455, 468, 481, 539, 553, 567, 581, 595, 660, 675, 690, 705, 720, 792, 867, 884, 901, 918, 935, 1017, 1035, 1053, 1140, 1230, 1250, 1270, 1290 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

FORMULA

a(n) = A000217(A002808(n)-3)-A000217(n-1).

EXAMPLE

a(1) = 1, a(2) = 2+3, a(3) = 3+4+5.

MATHEMATICA

Total[Range[#[[1]], #[[2]]-3]]&/@Module[{nn=80, cm}, cm=Select[ Range[ nn], CompositeQ]; Thread[{Range[Length[cm]], cm}]] (* Harvey P. Dale, Nov 04 2019 *)

CROSSREFS

Cf. A002808.

Sequence in context: A286276 A314273 A087090 * A314274 A184399 A314275

Adjacent sequences:  A161753 A161754 A161755 * A161757 A161758 A161759

KEYWORD

nonn,less

AUTHOR

Juri-Stepan Gerasimov, Jun 18 2009

EXTENSIONS

61 replaced by 75, 382 by 402 - R. J. Mathar, Sep 23 2009

STATUS

approved

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Last modified July 25 19:28 EDT 2021. Contains 346291 sequences. (Running on oeis4.)