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A184390 a(n) = sum of numbers from 1 to pi(n), where pi(n) = A007955(n). 5
1, 3, 6, 36, 15, 666, 28, 2080, 378, 5050, 66, 1493856, 91, 19306, 25425, 524800, 153, 17009028, 190, 32004000, 97461, 117370, 276, 55037822976, 7875, 228826, 266085, 240956128, 435, 328050405000 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

FORMULA

a(n) = Sum_(i = 1,…,pi(n)) i = A000217(A007955(n)) = 1/2*A007955(n)*(A007955(n)+1).

EXAMPLE

For n = 6; pi(6) = 36; a(n) = 1/2*36*37 = 666.

MATHEMATICA

# (#+1)/2&/@Array[Times@@Divisors[#]&, 40] (* Harvey P. Dale, Oct 05 2012 *)

CROSSREFS

Cf. A184387, A184388, A184389, A184391, A130674.

Sequence in context: A228279 A009197 A205336 * A130317 A019467 A106128

Adjacent sequences:  A184387 A184388 A184389 * A184391 A184392 A184393

KEYWORD

nonn

AUTHOR

Jaroslav Krizek, Jan 12 2011

STATUS

approved

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Last modified December 7 20:40 EST 2021. Contains 349589 sequences. (Running on oeis4.)