1,2

Table of n, a(n) for n=1..11.

Take the absolute value of the difference between counts of runs of 2 primes congruent to 1 mod 4 and 3 mod 4.

a(2)=3 because in A092639 the count is 2 and in A092640 the count is 5. 5 - 3 = 2.

Cf. A092639, A092640.

Sequence in context: A000220 A244705 A319643 * A077449 A152232 A183038

Adjacent sequences: A092638 A092639 A092640 * A092642 A092643 A092644

more,nonn

Enoch Haga, Mar 02 2004

a(9)-a(11) from Chai Wah Wu, Mar 18 2018

approved