OFFSET
1,26
COMMENTS
As in A167847 and in similar sequences, we map the digits of a number to a set of points and consider its graphical and geometrical properties.
LINKS
Rémy Sigrist, Illustration of a(10000) (using Pick's theorem)
Rémy Sigrist, PARI program for A302907
FORMULA
a(n) = 0 iff the n-th prime number belongs to A167847.
EXAMPLE
For n = 26:
- the 26th prime number is 101,
- the corresponding convex hull is as follows:
(1,1) +-----+ (3,1)
\ /
\ /
+ (2,0)
- it has area 1, hence a(26) = 2.
PROG
(PARI) See Links section.
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Rémy Sigrist, Dec 16 2018
STATUS
approved