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A306497 Abundant numbers that differ from the next abundant number by 5. 2
5391411025, 26957055120, 28816162375, 33426748350, 34393484125, 37739877175, 40342627320, 48150877770, 50866790970, 53356378075, 59305521270, 60711976320, 61164628525, 63395557225, 64899009175, 67275433225, 70088343325, 74922022170, 75665665075, 76781129425 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Since all multiples of 6 are abundant, numbers in this sequence have to be abundant numbers of the form 6n or 6n + 1.  Most common difference between abundant numbers is 6, followed by 2, 4, 3, 1. 5 is the least common.

LINKS

Table of n, a(n) for n=1..20.

FORMULA

Either a(n) or a(n)+5 are in A115414. - Amiram Eldar, Jul 16 2019

EXAMPLE

a(1) = 5391411025 is in the sequence since it is abundant and the next abundant number is 5391411030 which is a(1)+5 and all the numbers in between are deficient.

PROG

(PARI) isok(n) = for(k=1, 4, if(sigma(n+k) > 2*(n+k), return(0))); (sigma(n) > 2*n) && (sigma(n+5) > 2*(n+5)); \\ Daniel Suteu, Jul 24 2019

CROSSREFS

Cf. A005101, A096399, A231086, A228382, A316098, A316099, A115414, A125115.

Sequence in context: A017529 A321497 A133688 * A115414 A112430 A272714

Adjacent sequences:  A306494 A306495 A306496 * A306498 A306499 A306500

KEYWORD

nonn

AUTHOR

Sergio Pimentel, Feb 19 2019

EXTENSIONS

More terms from Amiram Eldar, Jul 16 2019

STATUS

approved

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Last modified June 1 02:09 EDT 2020. Contains 334758 sequences. (Running on oeis4.)