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A274810 Numbers n such that n and n+1 both have 38 divisors. 1
9399153082499072, 20164508489351168, 21992587709382656, 25039386409435136, 25537472011436031, 26756191491457023, 45443223518445567, 47474422651813887, 59772891590033408, 64241529683443712, 73381925783601152 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

PROG

(PARI) is(n)=numdiv(n)==38 && numdiv(n+1)==38

(PARI) has(n)=if(n%4==2, ispower(n/2, 18, &n) && isprime(n), bitand(n, 524287)==262144 && isprime(n>>18) && n>262144) \\ check if n is even with 38 divisors

list(lim)=my(v=List(), t); forprime(p=2, sqrtnint(lim\=1, 37), t=p^37; if(has(t+1), listput(v, t)); if(has(t-1), listput(v, t-1))); forprime(p=3, sqrtnint(lim\3, 18), my(p18=p^18); forprime(q=3, lim\p18, if(p==q, next); t=p18*q; if(has(t+1), listput(v, t)); if(has(t-1), listput(v, t-1)))); Set(v)

CROSSREFS

Intersection of A005237 and A175747.

Sequence in context: A104836 A247156 A320865 * A329948 A160405 A162032

Adjacent sequences:  A274807 A274808 A274809 * A274811 A274812 A274813

KEYWORD

nonn

AUTHOR

Charles R Greathouse IV, Jul 08 2016

STATUS

approved

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Last modified September 30 00:37 EDT 2020. Contains 337432 sequences. (Running on oeis4.)