OFFSET
1,1
LINKS
Lars Blomberg, Table of n, a(n) for n = 1..10000
EXAMPLE
prime 7489 -> 7489 + (7+4+8+9) = prime 7517 -> 7517 + (7+5+1+7) = prime 7537 -> 7537 + (7+5+3+7) = prime 7559 -> next iteration yields composite 7585.
MATHEMATICA
tiQ[p_]:=Boole[PrimeQ[NestList[#+Total[IntegerDigits[#]]&, p, 4]]]=={1, 1, 1, 1, 0}; Select[Prime[Range[20000]], tiQ] (* Harvey P. Dale, Dec 02 2024 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Patrick De Geest, May 15 1999
STATUS
approved