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A105087
Absolute difference between the sums of the left and right diagonals of ordered 2 X 2 prime squares.
0
1, 0, 0, 4, 2, 0, 0, 0, 0, 0, 0, 10, 4, 4, 2, 6, 2, 4, 2, 0, 0, 4, 10, 0, 6, 4, 0, 4, 8, 2, 6, 0, 2, 2, 2, 6, 6, 0, 0, 6, 2, 0, 2, 8, 4, 0, 0, 12, 4, 6, 10, 14, 2, 2, 28, 4, 4, 2, 6, 8, 2, 2, 0, 4, 14, 20, 10, 4, 0, 8, 6, 0, 4, 2, 14, 0, 4, 8, 0, 4, 4, 16, 10, 12, 2, 2, 0, 0, 2, 6, 8, 20, 6, 20, 6, 2, 2, 0
OFFSET
1,4
COMMENTS
The first 2 X 2 prime square of a set of ordered 2 X 2 prime squares begins with 2. Just a 2 X 2 prime square is any 4 consecutive primes arranged in a square formation.
FORMULA
A 2 X 2 ordered prime square is 4 consecutive primes arranged in a square of the form p(4n-3) p(4n-2) p(4n-1) p(4n) where n=1, 2, ... and Left diagonal is p(4n+1), p(4n) Right diagonal is p(4n+2), p(4n+3).
EXAMPLE
The 4th prime square is
41 43
47 53
sum of left diagonal = 41+53 = 94
sum of right diagonal = 43+47 = 90
difference = 4
So 4 is the 4th term.
PROG
(PARI) diffdiag(n) = { local(x, d1, d2); forstep(x=1, n, 4, d1=prime(x)+ prime(x+3); d2=prime(x+1)+ prime(x+2); print1(abs(d1-d2)", ") ) }
CROSSREFS
Sequence in context: A036115 A056582 A167891 * A238012 A324802 A320647
KEYWORD
easy,nonn
AUTHOR
Cino Hilliard, Apr 07 2005
STATUS
approved