OFFSET
1,1
COMMENTS
If a(n) is a record, then the n-th prime is in sequence A090481.
LINKS
T. D. Noe, Table of n, a(n) for n = 1..10000
FORMULA
MAPLE
taudiff := proc(n) numtheory[tau](n-1)+numtheory[tau](n+1) ; end proc: A175144 := proc(n) taudiff(ithprime(n)) ; end proc: seq(A175144(n), n=1..80) ; # R. J. Mathar, Mar 03 2010
MATHEMATICA
Table[p = Prime[n]; DivisorSigma[0, p - 1] + DivisorSigma[0, p + 1], {n, 100}]
Total[DivisorSigma[0, {#-1, #+1}]]&/@Prime[Range[80]] (* Harvey P. Dale, Feb 25 2012 *)
PROG
(PARI) a(n) = numdiv(prime(n)-1) + numdiv(prime(n)+1); \\ Amiram Eldar, Apr 17 2024
(PARI) lista(pmax) = forprime(p = 1, pmax, print1(numdiv(p-1) + numdiv(p+1), ", ")); \\ Amiram Eldar, Apr 17 2024
CROSSREFS
KEYWORD
nonn
AUTHOR
Leroy Quet, Feb 24 2010
EXTENSIONS
More terms from R. J. Mathar, Mar 03 2010
STATUS
approved