OFFSET
1,1
LINKS
Harry J. Smith, Table of n, a(n) for n = 1..1000
MATHEMATICA
Do[ If[ DivisorSigma[0, 2n - 1] == DivisorSigma[0, 2n + 1] == 10, Print[2n - 1]], {n, 1, 10^7} ]
2*SequencePosition[Table[If[DivisorSigma[0, n]==10, 1, 0], {n, 1, 11786879, 2}], {1, 1}][[All, 1]]-1 (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Apr 14 2019 *)
PROG
(PARI) for (n=1, 2000000, if ((numdiv(2*n-1)==10) && (numdiv(2*n+1)==10), write("tau=tau=10.txt", 2*n-1, "::", tau(2*n-1))))
(PARI) { n=0; for (m=1, 10^10, if ((numdiv(2*m-1)==10) && (numdiv(2*m+1)==10), write("b066690.txt", n++, " ", 2*m-1); if (n==1000, return)) ) } \\ Harry J. Smith, Mar 17 2010
CROSSREFS
KEYWORD
nonn
AUTHOR
Jon Perry, Jan 11 2002
EXTENSIONS
Edited by Dean Hickerson, Jan 13 2002
OFFSET changed from 0 to 1 by Harry J. Smith, Mar 17 2010
STATUS
approved