login
A073771
Highly composite numbers k such that 2*k is not a highly composite number.
2
4, 36, 48, 240, 720, 1680, 15120, 20160, 45360, 50400, 221760, 498960, 554400, 665280, 2882880, 6486480, 14414400, 17297280, 32432400, 43243200, 110270160, 245044800, 294053760, 735134400, 2095133040, 2205403200, 4655851200
OFFSET
1,1
COMMENTS
The terms were determined by means of A. Flammenkamp's list (cf. Links); the terms <= 17297280 were confirmed by a PARI program.
EXAMPLE
36 = A002182(7) is a term since 2*36 = 72 is not highly composite.
PROG
(PARI) {a=1; v=[1]; for(k=1, 40000000, b=numdiv(k); if(b>a, a=b; v=concat(v, k); while(2*v[1]<=k, if(2*v[1]<k, print1(v[1], ", ")); v=vecextract(v, "2.."))))}
CROSSREFS
Sequence in context: A274891 A062182 A308531 * A219247 A224094 A367511
KEYWORD
nonn
AUTHOR
Klaus Brockhaus, Aug 19 2002
STATUS
approved