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A023859 a(n) = 1*t(n) + 2*t(n-1) + ... + k*t(n+1-k), where k=floor((n+1)/2), and t = A023532. 1

%I #10 Jun 13 2019 20:48:53

%S 1,0,1,3,5,4,7,6,9,13,18,17,23,21,27,25,32,40,49,47,56,54,64,62,73,71,

%T 82,94,107,105,119,117,132,130,145,142,158,155,172,190,209,207,227,

%U 224,244,241,262,259,281,278,301,298,322,346,371,368,394,391,418,415,443,440,469,466

%N a(n) = 1*t(n) + 2*t(n-1) + ... + k*t(n+1-k), where k=floor((n+1)/2), and t = A023532.

%H Michael De Vlieger, <a href="/A023859/b023859.txt">Table of n, a(n) for n = 1..10000</a>

%t Array[Sum[k Boole@ Not@ IntegerQ@ Sqrt[8 # + 9] &[# + 1 - k], {k, Floor[(# + 1)/2]}] &, 64] (* _Michael De Vlieger_, Jun 12 2019 *)

%K nonn

%O 1,4

%A _Clark Kimberling_

%E Title simplified by _Sean A. Irvine_, Jun 12 2019

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Last modified April 17 23:23 EDT 2024. Contains 371767 sequences. (Running on oeis4.)