On a sequence arising in algebraic geometry.
On consecutive integer pairs with the same sum of distinct prime divisors.
On integer sequences associated with the cyclic and complete graphs.
On sum-free sequences
Portraits of Numbers
Prime and composite terms in Sloane's sequence A056542.
Primes of the form .
Ramanujan type trigonometric formulas: the general form for the argument .
Rational tree morphisms and transducer integer sequences: definition and examples.
Refactorable numbers -- a machine invention.
Self-describing sequences and the Catalan family tree.
Sequences of definite integrals, factorials and double factorials.
Series and iterations for 1/π
Some alternating sums of Lucas numbers
We consider alternating sums of squares of odd and even terms of the Lucas sequence and alternating sums of their products. These alternating sums have nice representations as products of appropriate Fibonacci and Lucas numbers.
Some remarks on differentiable sequences and recursivity.
Staircases in .
Stapled sequences and stapling coverings of natural numbers.
Sums of squares and products of Jacobsthal numbers.
The -adic valuations of sequences counting alternating sign matrices.
Young tableaux and other mutually describing sequences.