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A161912
a(n) = A040976(n+1) - A006218(n).
7
0, 0, 0, 0, 1, 1, 1, 1, 1, 4, 2, 6, 4, 4, 4, 6, 7, 7, 7, 9, 5, 7, 7, 11, 11, 12, 10, 10, 6, 8, 14, 16, 16, 14, 20, 18, 15, 19, 19, 21, 19, 19, 21, 21, 19, 15, 23, 33, 27, 26, 24, 26, 22, 30, 28, 30, 28, 26, 28, 30, 20, 28, 38, 36, 31, 31, 37, 41, 45, 43, 39, 43, 39, 43, 45, 43, 43, 47, 43, 49, 49
OFFSET
0,10
MAPLE
A006218 := proc(n) add(floor(n/k), k=1..n) ; end:
A040976 := proc(n) ithprime(n)-2 ; end:
A161912 := proc(n) A040976(n+1)-A006218(n) ; end:
seq(A161912(n), n=0..120) ; # R. J. Mathar, Jul 01 2009
PROG
(PARI) first(n)=my(v=primes(n+1), s); v[1]-=s=2; forfactored(k=1, n, v[k[1]+1]-=s+=numdiv(k)); v \\ Charles R Greathouse IV, Nov 03 2021
CROSSREFS
KEYWORD
easy,nonn,less
AUTHOR
Omar E. Pol, Jun 28 2009
EXTENSIONS
Invalid formula deleted and sequence extended by R. J. Mathar, Jul 01 2009
STATUS
approved