Logo

Greetings from The On-Line Encyclopedia of Integer Sequences!

Hints

Search: id:A002952
Displaying 1-1 of 1 results found. page 1
     Format: long | short | internal | text      Sort: relevance | references | number      Highlight: on | off
A002952 Smaller of unitary amicable pair.
(Formerly M5372)
+0
4
114, 1140, 18018, 32130, 44772, 56430, 67158, 142310, 180180, 197340, 241110, 296010, 308220, 462330, 591030, 669900, 671580, 785148, 815100, 1004850, 1077890, 1080150, 1156870, 1177722, 1222650, 1281540, 1475810, 1511930, 1571388 (list; graph; listen)
OFFSET

1,1

COMMENT

I proved the following facts: (a) If (m,n) is a unitary amicable pair such that mod(m,4)= mod(n,4)=2 and 5 doesn't divide m*n then (10*m,10*n) is a unitary amicable pair. (b) If (m,n) is a unitary amicable pair such that m/12 and n/12 are natural numbers and gcd(m/12,12)=gcd(n/12,12)=1 then (3/2*m,3/2*n) is a unitary amicable pair. - Farideh Firoozbakht (f.firoozbakht(AT)math.ui.ac.ir), Nov 27 2005

REFERENCES

P. Hagis, Jr., Unitary amicable numbers, Math. Comp., 25 (1971), 915-918.

LINKS

J. M. Pedersen, Known Unitary Amicable Pairs

I. Peterson, Math Trek

Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.

J. O. M. Pedersen, Tables of Aliquot Cycles

EXAMPLE

(114,126) is a unitary amicable pair: 114 has unitary divisors 1, (2,57), (3,38) and (6,19), apart from 114 itself. Their sum is 126, whose unitary divisors < 126 are 1, (2,63), (7,18), (9,14) whose sum is 114.

CROSSREFS

Cf. A002953, A063991, A111904.

Adjacent sequences: A002949 A002950 A002951 this_sequence A002953 A002954 A002955

Sequence in context: A043403 A122279 A126169 this_sequence A108344 A112485 A084877

KEYWORD

nonn,nice

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com); extended Nov 24 2005

page 1

Search completed in 0.002 seconds

Lookup | Welcome | Find friends | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
More pages | Superseeker | Maintained by N. J. A. Sloane (njas@research.att.com)

Last modified July 4 09:27 EDT 2009. Contains 160562 sequences.


AT&T Labs Research