A274366 - OEIS

%I #7 Jul 02 2016 00:54:34

%S 2200933376,3724751871,4982377472,5055007743,5828903936,6506195967,

%T 9771369471,12238318592,13810439168,15213325311,15503492096,

%U 15624424448,17027310591,20703583232,22590198783,23194860543,27596727296,28274019327,30136306688,30450801663

%N Numbers n such that n and n+1 both have 22 divisors.

%H Charles R Greathouse IV, <a href="/A274366/b274366.txt">Table of n, a(n) for n = 1..10000</a>

%o (PARI) is(n)=numdiv(n)==22 && numdiv(n+1)==22

%o (PARI) list(lim)=my(v=List(), t); forprime(p=2, sqrtnint(lim\=1, 21), t=p^21; if(numdiv(t+1)==22, listput(v, t)); if(numdiv(t-1)==22, listput(v, t-1))); forprime(p=3, sqrtnint(lim\3, 10), my(p10=p^10); forprime(q=3, lim\p10, if(p==q, next); t=p10*q; if(numdiv(t+1)==22, listput(v, t)); if(numdiv(t-1)==22, listput(v, t-1)))); Set(v)

%Y Intersection of A005237 and A137485.

%K nonn

%O 1,1

%A _Charles R Greathouse IV_, Jun 19 2016