OFFSET
1,2
LINKS
K. D. Bajpai, Table of n, a(n) for n = 1..10000
EXAMPLE
MATHEMATICA
A247016 = {}; Do[t = n*(n + 1)/2; If[Intersection[IntegerDigits[t], {1, 4, 7}] == {}, AppendTo[A247016, t]], {n, 0, 500}]; A247016
Select[Accumulate[Range[0, 300]], DigitCount[#, 10, 1]==DigitCount[#, 10, 4] == DigitCount[ #, 10, 7] == 0&] (* Harvey P. Dale, Apr 18 2019 *)
PROG
(Python)
for n in range(2, 10**3):
..s = str(int(n*(n-1)/2))
..if not (s.count('1') + s.count('4') + s.count('7')):
....print(int(s), end=', ') # Derek Orr, Sep 18 2014
CROSSREFS
KEYWORD
nonn,base,less
AUTHOR
K. D. Bajpai, Sep 09 2014
EXTENSIONS
Added starting number 0 (suggested by D. Orr), added A-number in the name and examples. - Wolfdieter Lang, Oct 06 2014
STATUS
approved