

A160907


Sum of the number of prime divisors including repetitions between n^2 and (n+1)^2.


1



4, 11, 17, 23, 30, 34, 42, 50, 54, 58, 67, 73, 78, 85, 95, 99, 103, 111, 117, 124, 128, 140, 143, 151, 157, 163, 174, 174, 183, 187, 197, 210, 207, 217, 222, 229, 235, 244, 251, 256, 261, 270, 276, 285, 293, 298, 304, 311, 318, 327, 331, 334, 347, 352, 362, 366
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OFFSET

1,1


LINKS

Table of n, a(n) for n=1..56.


EXAMPLE

Between 1^2 and 2^2 we have 0,1,1,2 which sum to 4, so a(1)=4.
Between 2^2 and 3^2 we have 2,1,2,1,3,2 which sum to 11, so a(2)=11.


MATHEMATICA

f[n_]:=If[n==1, 0, Plus@@Last/@FactorInteger[n]]; Table[Sum[f[j], {j, i^2, (i+1)^2}], {i, 60}] (*Chandler*)


CROSSREFS

Cf. A001222.
Sequence in context: A310561 A248349 A246301 * A003146 A063237 A026381
Adjacent sequences: A160904 A160905 A160906 * A160908 A160909 A160910


KEYWORD

easy,nonn


AUTHOR

Daniel Tisdale, May 29 2009


EXTENSIONS

Edited and extended by Ray Chandler, May 06 2010


STATUS

approved



