

A074372


1 + the sum of the distinct primes dividing n.


4



1, 3, 4, 3, 6, 6, 8, 3, 4, 8, 12, 6, 14, 10, 9, 3, 18, 6, 20, 8, 11, 14, 24, 6, 6, 16, 4, 10, 30, 11, 32, 3, 15, 20, 13, 6, 38, 22, 17, 8, 42, 13, 44, 14, 9, 26, 48, 6, 8, 8, 21, 16, 54, 6, 17, 10, 23, 32, 60, 11, 62, 34, 11, 3, 19, 17, 68, 20, 27, 15, 72, 6, 74, 40, 9, 22, 19, 19, 80, 8
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OFFSET

1,2


COMMENTS

Number of maximal subgroups in dihedral group of order 2n.  Eric M. Schmidt, Oct 14 2014


LINKS

Table of n, a(n) for n=1..80.
Neville Holmes, Integer Sequences


FORMULA

a(n) = 1 + A008472(n).


EXAMPLE

2: 3 (1+2); 3: 4 (1+3); 4: 3 (1+2); 5: 6 (1+5); 6: 6 (1+2+3); ...


MAPLE

with(numtheory): a:=proc(n) local F: F:=convert(factorset(n), list): 1+sum(F[j], j=1..nops(F)) end: seq(a(n), n=1..90); # Emeric Deutsch, Mar 12 2005


MATHEMATICA

Rest[ Range[0, 20] CoefficientList[ Log[E, Series[(1/(1  x)) Product[ 1/(1  x^Prime[j]), {j, 200}], {x, 0, 20}]], x]] (* Robert G. Wilson v, Aug 16 2011 *)


CROSSREFS

Cf. A001414, A008472, A036288.
Sequence in context: A136195 A117892 A286098 * A049276 A101684 A061800
Adjacent sequences: A074369 A074370 A074371 * A074373 A074374 A074375


KEYWORD

easy,nonn


AUTHOR

W. Neville Holmes, Aug 22 2002


EXTENSIONS

Corrected and extended by Emeric Deutsch, Mar 12 2005


STATUS

approved



