Decomposition into weight × level + jump - all 2D graphs

Areas of Pythagorean (or right-angled) triangles with integer sides of the form (2mn, m^2-n^2, m^2+n^2).

A073120(n) = A000000(n) * A000000(n) + A000000(n)

a(n) = r*a(ceiling(n/2))+s*a(floor(n/2)) with a(1)=1 and (r,s)=(2,2).

A073121(n) = A000000(n) * A000000(n) + A000000(n)

Squarefree numbers n such that n-1 and n+1 are not squarefree.

A073247(n) = A000000(n) * A000000(n) + A000000(n)

Irregular primes (A000928) with irregularity index one.

A073276(n) = A000000(n) * A000000(n) + A000000(n)

Irregular primes with irregularity index two.

A073277(n) = A000000(n) * A000000(n) + A000000(n)

Numbers having at least one prime gap in their factorization.

A073492(n) = A000000(n) * A000000(n) + A000000(n)

Numbers having exactly one prime gap in their factorization.

A073493(n) = A000000(n) * A000000(n) + A000000(n)

Sum of primes whose index is congruent to n (mod 3); equals the partial sums of A073737 (in which sums of three successive terms form the primes).

A073736(n) = A000000(n) * A000000(n) + A073737(n+2)

Numbers n such that sigma(n) is divisible by 6.

A074627(n) = A000000(n) * A000000(n) + A000000(n)

Sum of squares of gaps between consecutive primes.

A074741(n) = A000000(n) * A000000(n) + A076821(n+1)