

A109806


Admirable numbers such that the subtracted divisor is square.


1



20, 56, 104, 368, 464, 650, 836, 992, 1952, 8415, 11096, 16256, 17816, 28544, 31815, 45356, 77744, 83312, 91388, 98048, 113072, 122624, 128768, 130304, 254012, 351351, 388076, 507392, 522752, 537248, 698528, 780975, 791264, 1081568
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OFFSET

1,1


LINKS



EXAMPLE

a(2)=56 because 1+2+7+8+14+284 = 56 and the subtracted divisor is square.


MATHEMATICA

aQ[n_] := (d = DivisorSigma[1, n]  2n) > 0 && EvenQ[d] && Mod[n, d/2] == 0 && d < 2n && IntegerQ @ Sqrt[d/2]; Select[Range[10^5], aQ] (* Amiram Eldar, Sep 22 2019 *)


CROSSREFS



KEYWORD

nonn


AUTHOR



STATUS

approved



