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A095119 Numbers n such that s(n) >= sigma(n), where s(n) = A095118(n) is the sum of the squares of the divisors of n which are <= sqrt(n) and sigma(n) = A000203(n) is the sum of the divisors of n. 2
1, 840, 900, 1080, 1225, 1260, 1440, 1600, 1680, 1800, 1848, 1890, 1980, 2016, 2100, 2160, 2340, 2400, 2520, 2640, 2700, 2772, 2800, 2880, 2970, 3024, 3080, 3120, 3136, 3150, 3240, 3276, 3300, 3360, 3465, 3528, 3600, 3640, 3696, 3780, 3900, 3960, 3969 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

EXAMPLE

840 is in the sequence because s(840) = 3070 >= 2880 = sigma(840).

MATHEMATICA

s[n_]:=Plus@@(Select[Divisors[n], #^2<=n&]^2); Select[Range[4000], s[ # ]>=DivisorSigma[1, # ]&]

PROG

(PARI) isok(n) = sumdiv(n, d, if (d^2 <= n, d^2)) >= sigma(n); \\ Michel Marcus, Aug 13 2019

CROSSREFS

Cf. A000203, A095118.

Sequence in context: A156937 A135640 A306854 * A175742 A102793 A144770

Adjacent sequences:  A095116 A095117 A095118 * A095120 A095121 A095122

KEYWORD

nonn

AUTHOR

Dean Hickerson, following a suggestion of Leroy Quet, May 28 2004

STATUS

approved

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Last modified November 18 12:16 EST 2019. Contains 329261 sequences. (Running on oeis4.)