OFFSET
1,2
LINKS
Robert Israel, Table of n, a(n) for n = 1..1000
EXAMPLE
13578 is here since 13578 = 2.3.31.'73' and 13579 = '37'.367.
MAPLE
revdigs:= proc(n) option remember; local L, i;
L:= convert(n, base, 10);
add(L[-i]*10^(i-1), i=1..nops(L));
end proc:
filter:= proc(n) local p;
p:= revdigs(max(numtheory:-factorset(n)));
isprime(p) and p = min(numtheory:-factorset(n+1))
end proc:
filter(1):= true:
select(filter, [$1..10000]); # Robert Israel, Apr 02 2020
MATHEMATICA
Join[{1}, Select[Range[65000], IntegerReverse[FactorInteger[#][[-1, 1]]] == FactorInteger[ #+1][[1, 1]]&]] (* Harvey P. Dale, Mar 29 2018 *)
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Jason Earls, Jun 12 2002
STATUS
approved