primitive semiperfect number

Parse the sequence of semiperfect numbers in ascending order, striking out any numbers that are divisible by any smaller number in the sequence. A number that remains after this process is then called a primitive semiperfect number or primitive pseudoperfect number. Put another way, none of the divisors of a primitive semiperfect number are themselves semiperfect. The first few primitive semiperfect numbers are 6, 20, 28, 88, 104, 272, 304, 350, listed in A6036 of Sloane’s OEIS.

The list of the largest prime factors of each of the primitive semiperfect numbers gives the list of prime numbers almost in order but with many duplicates interspersed.

The smallest odd primitive semiperfect number is 945, which is also the smallest odd abundant number.

单词	PrimitiveSemiperfectNumber
释义	primitive semiperfect number Parse the sequence of semiperfect numbers in ascending order, striking out any numbers that are divisible by any smaller number in the sequence. A number that remains after this process is then called a primitive semiperfect number or primitive pseudoperfect number. Put another way, none of the divisors of a primitive semiperfect number are themselves semiperfect. The first few primitive semiperfect numbers are 6, 20, 28, 88, 104, 272, 304, 350, listed in A6036 of Sloane’s OEIS. The list of the largest prime factors of each of the primitive semiperfect numbers gives the list of prime numbers almost in order but with many duplicates interspersed. The smallest odd primitive semiperfect number is 945, which is also the smallest odd abundant number.
随便看	Boolean algebra homomorphism BooleanDomain Boolean domain BooleanIdeal Boolean ideal BooleanLattice Boolean lattice BooleanOperationsOnAutomata Boolean operations on automata BooleanPrimeIdealTheorem Boolean prime ideal theorem BooleanQuotientAlgebra Boolean quotient algebra BooleanRing Boolean ring BooleanSubalgebra Boolean subalgebra BooleanvaluedFunction Boolean-valued function BooleanValuedModel Boolean valued model BooleInequality Boole inequality BooleInequalityProofOf Boole inequality, proof of