OFFSET
1,1
COMMENTS
See A081705 for the definition of n-tuply abundant. - David Wasserman, Jun 24 2004
EXAMPLE
a(3)=78 because 78 is the smallest number that is exactly triply abundant, with this aliquot chain: 78->90->144->259->45.
PROG
(PARI) LIMIT = 50; A = vector(LIMIT); count = 0; i = 1; while (count < LIMIT, i = i + 1; ab = 0; lastn = i; n = sigma(i) - i; while(ab <= LIMIT && n > lastn, ab = ab + 1; lastn = n; n = sigma(lastn) - n); if(ab <= LIMIT && ab > 0 && A[ab] == 0, A[ab] = i; count = count + 1)); A \\ David Wasserman, Jun 24 2004
CROSSREFS
KEYWORD
nonn
AUTHOR
Gabriel Cunningham (gcasey(AT)mit.edu), Apr 08 2003
EXTENSIONS
More terms from David Wasserman, Jun 24 2004
STATUS
approved