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A103288 Numbers n such that sigma(n) >= 2n-1 (union of perfect, abundant and least deficient numbers). 8
1, 2, 4, 6, 8, 12, 16, 18, 20, 24, 28, 30, 32, 36, 40, 42, 48, 54, 56, 60, 64, 66, 70, 72, 78, 80, 84, 88, 90, 96, 100, 102, 104, 108, 112, 114, 120, 126, 128, 132, 138, 140, 144, 150, 156, 160, 162, 168, 174, 176, 180, 186, 192, 196, 198, 200, 204, 208, 210, 216, 220 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

If the only least deficient numbers are the powers of 2 (open problem) then this sequence is a union of A023196 and A000079.

LINKS

T. D. Noe, Table of n, a(n) for n=1..1000

FORMULA

Such n that A004125(n) <= A004125(n-1)

PROG

(PARI) for(n=1, 1000, if(sigma(n)>=2*n-1, print(n)));

CROSSREFS

Cf. A023196, A023197, A023198, A023199, A000079, A004125.

Sequence in context: A087086 A301587 A319796 * A125225 A092903 A005153

Adjacent sequences:  A103285 A103286 A103287 * A103289 A103290 A103291

KEYWORD

nonn

AUTHOR

Max Alekseyev, Jan 28 2005

STATUS

approved

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Last modified May 25 20:58 EDT 2020. Contains 334597 sequences. (Running on oeis4.)