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A078713 Sum of squares of the distances between successive divisors of n. 2
0, 1, 4, 5, 16, 11, 36, 21, 40, 35, 100, 43, 144, 75, 108, 85, 256, 101, 324, 131, 216, 203, 484, 171, 416, 291, 364, 259, 784, 273, 900, 341, 552, 515, 804, 385, 1296, 651, 780, 519, 1600, 551, 1764, 659, 960, 971, 2116, 683, 1800, 885, 1356, 931, 2704, 911, 1988 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

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

EXAMPLE

The divisors of 10 are 1, 2, 5, 10 and the sum of the squares of the distances between successive divisors = (2-1)^2 + (5-2)^2 + (10-5)^2 = 35. Hence a(10) = 35.

MATHEMATICA

f[n_] := Module[{d, l, s, i}, d = Divisors[n]; l = Length[d]; s = 0; For[i = 1, i < l, i++, s = s + (d[[i + 1]] - d[[i]])^2]; s]; Table[f[n], {n, 1, 100}]

Table[Total[Differences[Divisors[n]]^2], {n, 60}] (* Harvey P. Dale, Apr 10 2018 *)

CROSSREFS

Sequence in context: A244643 A085768 A166304 * A175263 A000695 A081345

Adjacent sequences:  A078710 A078711 A078712 * A078714 A078715 A078716

KEYWORD

nonn

AUTHOR

Joseph L. Pe, Dec 19 2002

STATUS

approved

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Last modified December 10 03:07 EST 2018. Contains 318044 sequences. (Running on oeis4.)