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 A192291 Couple of numbers a, b for which sigma*(a)=b and sigma(b)-b=a, where sigma*(n) is the sum of the anti-divisors of n. 3
 10, 14, 32, 58, 154, 182, 382, 758, 3830, 5962, 67815454, 94941602, 7172169026, 8196764584, 18624907238, 34790550682, 30033199624, 31387575416, 38857270202, 48571587730 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS a(21) > 10^11. - Hiroaki Yamanouchi, Sep 28 2015 LINKS EXAMPLE sigma*(10) = 3+4+7 = 14. sigma(14)-14 = 1+2+7 = 10. sigma*(32)= 3+5+7+9+13+21 = 58. sigma(58)-58 = 1+2+29 = 32. MAPLE with(numtheory); P:= proc(n) local a, b, c, i, ks; for i from 3 to n do a:={}; for k from 2 to i-1 do if abs((i mod k)- k/2) < 1 then a:=a union {k}; fi; od; b:=nops(a); c:=op(a); s:=0; for k from 1 to b do s:=s+c[k]; od; if sigma(s)-s=i then print(i, s); fi; od; end: P(10000); CROSSREFS Cf. A063990, A066272, A192290, A192292, A192293. Sequence in context: A241162 A164765 A116955 * A144967 A328635 A260564 Adjacent sequences: A192288 A192289 A192290 * A192292 A192293 A192294 KEYWORD nonn,more AUTHOR Paolo P. Lava, Jun 29 2011 EXTENSIONS a(11)-a(20) from Hiroaki Yamanouchi, Sep 28 2015 STATUS approved

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Last modified March 29 11:38 EDT 2023. Contains 361599 sequences. (Running on oeis4.)