OFFSET
1,2
COMMENTS
Does lcm(1..10) = 2520 divide a(n) for all n > 1?
Does lcm(1..11) = 27720 divide a(n) for all n except 1, 3, and 16?
LINKS
Michel Marcus, Table of n, a(n) for n = 1..77
EXAMPLE
50400 is in the sequence because sigma(50400) - 4*50400 = 203112 - 201600 = 1512, and no k < 50400 has a value of sigma(k) - 4k this large.
PROG
(PARI) lista(nn) = {m = -oo; k = 0; for (n=1, nn, if ((nm = (sigma(n) - 4*n)) > m, k++; print1(n, ", "); m = nm); ); } \\ Michel Marcus, Nov 02 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
Jon E. Schoenfield, Jan 30 2017
STATUS
approved