A335795 First differences of A335794.

0, 1, 6, 6, 18, 6, 30, 18, 54, 6, 30, 30, 78, 18, 90, 54, 150, 6, 30, 30, 78, 30, 126, 78, 222, 18, 90, 90, 234, 54, 246, 150, 390, 6, 30, 30, 78, 30, 126, 78, 222, 30, 126, 126, 318, 78, 366, 222, 606, 18, 90, 90, 234, 90, 378, 234, 666, 54, 246, 246, 630, 150, 630, 390, 966, 6, 30, 30, 78, 30, 126, 78, 222, 30, 126, 126, 318

Offset: 0

Author

Cody B Duncan, Jun 23 2020

Keywords

• nonn

Comments

Position of 6 occurs every 2^(n-1) + 1 for n > 0.

Position of 18 appears to occur according to the tetranacci numbers (cf. A000288): 4, 7, 13, 25, 49, ...

Examples

			When written as a triangle:
0
1
6
6 18
6 30 18 54
6 30 30 78 18 90  54 150
6 30 30 78 30 126 78 222 18 90 90 234 54 246 150 390
...
		

References

• S. M. Ulam, On some mathematical problems connected with patterns of growth of figures, pp. 215-224 of R. E. Bellman, ed., Mathematical Problems in the Biological Sciences, Proc. Sympos. Applied Math., Vol. 14, Amer. Math. Soc., 1962 (see Example 6, page 224).

Crossrefs

Cf. A000288, A151723, A335794.