OFFSET
1,2
COMMENTS
Former name was: Smallest x such that p(n) = Sigma[x] - 1. That did not match the Data. See A296375 for that sequence.
LINKS
Iain Fox, Table of n, a(n) for n = 1..10000
FORMULA
a(n+1)-a(n) = A066075(n).
MAPLE
N:= 100: # To get a(1)..a(N)
P:= ithprime(N-1):
S:= select(t -> isprime(t) and t <= P, map(-1+numtheory:-sigma, [$1..P])):
T:= Statistics:-Tally(sort(S), output=table):
ListTools:-PartialSums([1, seq(T[ithprime(i)], i=1..N-1)]); # Robert Israel, Dec 27 2017
PROG
(PARI) first(n) = my(res = vector(n), a = 1); res[1] = 1; for(k=2, n, for(x=1, prime(k-1), if(prime(k-1) == (sigma(x) - 1), a++)); res[k] = a); res \\ Iain Fox, Dec 28 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
Labos Elemer, Dec 03 2001
EXTENSIONS
Edited by Robert Israel, Dec 27 2017
STATUS
approved