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A225684 Nonpalindromic numbers n with property that the sum of the reversed divisors of n is equal to n+1. 0
965, 8150, 12966911, 625261742 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Palindromes are excluded because palindromic primes automatically have this property, and palindromic nonprimes never have it.

Call a number "quasi-perfect" or "slightly excessive" if sigma(n) = 2n+1 (cf. A000203). It is conjectured that no quasi-perfect number exists. The present sequence is a variation that certainly has at least four terms.

a(5) > 10^11. - Donovan Johnson, May 26 2013

LINKS

Table of n, a(n) for n=1..4.

Jason Earls, All About Reversed Slightly Excessive Numbers

Eric Weisstein's World of Mathematics, Quasi-perfect number

EXAMPLE

The divisors of 965 are 1, 5, 193, 965, and reversing and adding produces 1 + 5 + 391 + 569 = 966.

CROSSREFS

Cf. A069192, A069250, A000203.

Sequence in context: A267996 A093232 A252259 * A186468 A014363 A260291

Adjacent sequences:  A225681 A225682 A225683 * A225685 A225686 A225687

KEYWORD

nonn,base,more

AUTHOR

N. J. A. Sloane, May 19 2013

EXTENSIONS

a(4) from Donovan Johnson, May 19 2013

STATUS

approved

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Last modified July 17 02:10 EDT 2019. Contains 325092 sequences. (Running on oeis4.)