OFFSET
1,1
COMMENTS
None of the digits can be 0,4,6,8 or 9. All the digits must be 1 or, just one digit can be 2,3,5 or 7 and all the others are 1.
There are no more terms less than 10^2580. - Hans Havermann, May 07 2006
EXAMPLE
1711 is in the sequence because (1)it is a triangular number and (2)the product of its digits is 1*7*1*1=7, which is a prime number.
MATHEMATICA
Select[Accumulate[Range[100000]], PrimeQ[Times@@IntegerDigits[#]]&] (* _Harvey Dale_, Dec 04 2010 *)
Select[Table[n(n + 1)/2, {n, 10^3}], PrimeQ[Times@@IntegerDigits[#]]&] (* Zak Seidov, Dec 04 2010 *)
PROG
(PARI) isok(t) = ispolygonal(t, 3) && isprime(vecprod(digits(t))); \\ Michel Marcus, Jul 16 2022
CROSSREFS
KEYWORD
more,nonn,base
AUTHOR
Luc Stevens (lms022(AT)yahoo.com), Apr 29 2006
STATUS
approved