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Numbers m such that m*(prime(m)+1) is a square.
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%I #14 Feb 18 2021 05:41:32

%S 150,1274,7776,37631,96625,1436778,1617173,8751645,11873964,78580934,

%T 391317723,403263375,429830078,1653987950,1989687200,2125840598,

%U 2546468442,8179002128,8179002164,8179002192,30860615042,31374585176

%N Numbers m such that m*(prime(m)+1) is a square.

%C a(23) > pi(10^12). [_Donovan Johnson_, Feb 26 2010]

%p for i from 1 to 250000 do `if`(issqr(i*(ithprime(i)+1))=true,i,NULL); od;

%o (PARI) isok(m) = issquare(m*(prime(m)+1)); \\ _Michel Marcus_, Feb 18 2021

%Y Cf. A083726.

%K nonn,more

%O 1,1

%A _Benoit Cloitre_, Aug 29 2002

%E More terms from Francois Jooste (pin(AT)myway.com), Mar 16 2003

%E a(6)-a(22) from _Donovan Johnson_, Feb 26 2010