OFFSET
0,1
COMMENTS
After the initial 2, numbers with either one 2 or two 1's in their primorial base representation (A049345), with all the other digits zeros.
LINKS
EXAMPLE
Triangle begins as:
2;
3, 4;
7, 8, 12;
31, 32, 36, 60;
211, 212, 216, 240, 420;
2311, 2312, 2316, 2340, 2520, 4620;
30031, 30032, 30036, 30060, 30240, 32340, 60060;
510511, 510512, 510516, 510540, 510720, 512820, 540540, 1021020;
9699691, 9699692, 9699696, 9699720, 9699900, 9702000, 9729720, 10210200, 19399380;
PROG
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Antti Karttunen, Feb 29 2024
STATUS
approved