OFFSET
0,2
COMMENTS
Each number is the smallest prime => the sum of the 2 numbers above (consider each line padded with 0 on each side).
FORMULA
Array read by rows: A[k+1,n] = nextprime(A[k,n] + A[k,n+1]) = A007918(A[k,n] + A[k,n+1]).
EXAMPLE
Triangle begins:
1
2....2
3....5....3
5...11...11....5
7...17...23...17....7
11..29...41...41...29...11
13..41...71...83...71...41...13
17..59..113..157..157..113...59...17
19..79..173..271..317..271..173...79...19
23.101..257..449..593..593..449..257..101...23
29.127..359..709.1049.1187.1049..709..359..127..29
31.157..487.1069.1759.2237.2237.1759.1069..487.157..31
37.191..647.1559.2833.4001.4583.4001.2833.1559.647.191.37.
First column is primes A000040. Second column is A064337. Analog of central binomial coefficient A000984 is the central numbers in this triangle, beginning: 1, 5, 23, 83, 317, 1187, 4583, 17327. Different triangles result if the first row is a pair other than (2,2). Asymmetric triangles occur if the first row consists of unequal integers.
The number under the middle of the row (2, 2) is 5 because 5 is smallest prime equal to or greater than 2+2 = 4.
CROSSREFS
KEYWORD
AUTHOR
Jonathan Vos Post, Nov 12 2007
STATUS
approved