OFFSET
1,1
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
EXAMPLE
a(3) = 60 is a term because 60-1 = 59 and 60+1 = 61 are primes, A001414(60) = 2+2+3+5 = 12, and 12-1 = 11 and 12+1 = 13 are primes.
MAPLE
spf:= proc(n) local F, t;
F:= ifactors(n)[2];
add(t[1]*t[2], t=F)
end proc:
R:= 4: count:= 1:
for t from 6 by 6 while count < 100 do
if isprime(t-1) and isprime(t+1) then
s:= spf(t);
if isprime(s-1) and isprime(s+1) then
count:= count+1;
R:= R, t;
fi
fi
od:
R;
MATHEMATICA
Select[Prime@Range@8000, PrimeQ[#+2]&&And@@PrimeQ[Total[Flatten[Table@@@FactorInteger[#+1]]]+{1, -1}]&]+1 (* Giorgos Kalogeropoulos, Nov 18 2021 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
J. M. Bergot and Robert Israel, Nov 17 2021
STATUS
approved