OFFSET
1,1
COMMENTS
The 6th term has 6 digits; the 44th term has 44 digits.
The 685th term has 349 digits.
LINKS
K. D. Bajpai, Table of n, a(n) for n = 1..1000
EXAMPLE
43 is in the sequence because (5! + 7!)/ 5! = (120 + 5040)/120 = 43 which is prime and 5 and 7 are consecutive primes.
157 is in the sequence because (11! + 13!)/ 11! = (39916800 + 6227020800)/ 39916800 = 157 which is prime and 11 and 13 are consecutive primes.
MAPLE
KD := proc() local a, b, d; a:=ithprime(n); b:=ithprime(n+1); d:=(a! + b!)/ a!; if isprime(d) then RETURN (d); fi; end: seq(KD(), n=1..300);
MATHEMATICA
Select[((#[[1]]!+#[[2]]!)/#[[1]]!&/@Partition[Prime[Range[ 300]], 2, 1]), PrimeQ] (* Harvey P. Dale, Mar 07 2019 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
K. D. Bajpai, Jan 09 2014
STATUS
approved