A383939 - cp's OEIS frontend

A383939 Numbers k such that k and the k-th triangular number T(k) = k*(k+1)/2 have only even digits.

n	a(n)
1	0
2	28
3	40
4	64
5	400
6	2828
7	4000
8	4064
9	6428
10	22840
11	24028
12	40000
13	202428
14	240028
15	400000
16	2040040
17	2400028
18	4000000
19	6422840
20	6428064
21	6646624
22	20044064
23	20202080
24	20400040
25	20406080
26	24000028
27	40000000
28	66400064
29	200042428
30	204000040
31	228406080
32	240000028

[0, 28, 40, 64, 400, 2828, 4000, 4064, 6428, 22840, 24028, 40000, 202428, 240028, 400000, 2040040, 2400028, 4000000, 6422840, 6428064, 6646624, 20044064, 20202080, 20400040, 20406080, 24000028, 40000000, 66400064, 200042428, 204000040, 228406080, 240000028]

cp's OEIS Frontend

A383939 Numbers k such that k and the k-th triangular number T(k) = k*(k+1)/2 have only even digits.

Table of values

List of values