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A136195 Irregular array read by rows: row n contains the sums of each pair of consecutive positive divisors of n. 1
3, 4, 3, 6, 6, 3, 5, 9, 8, 3, 6, 12, 4, 12, 3, 7, 15, 12, 3, 5, 7, 10, 18, 14, 3, 9, 21, 4, 8, 20, 3, 6, 12, 24, 18, 3, 5, 9, 15, 27, 20, 3, 6, 9, 15, 30, 4, 10, 28, 3, 13, 33, 24, 3, 5, 7, 10, 14, 20, 36, 6, 30, 3, 15, 39, 4, 12, 36, 3, 6, 11, 21, 42, 30, 3, 5, 8, 11, 16, 25, 45 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,1

COMMENTS

The first listed row is row 2. Row n contains d(n)-1 terms, where d(n) is the number of positive divisors of n.

LINKS

Table of n, a(n) for n=2..82.

EXAMPLE

The positive divisors of 20 are 1,2,4,5,10,20. 1+2=3. 2+4=6. 4+5=9. 5+10=15. 10+20=30. So row 20 is (3,6,9,15,30).

MAPLE

with(numtheory): a:=proc(n) local dn: dn:=divisors(n): seq(dn[i]+dn[i+1], i= 1..nops(dn)-1) end proc: for n from 2 to 30 do a(n) end do; # Emeric Deutsch, Jan 05 2008

CROSSREFS

Cf. A136193, A032741 (row lengths).

Sequence in context: A248006 A197699 A005092 * A117892 A286098 A074372

Adjacent sequences:  A136192 A136193 A136194 * A136196 A136197 A136198

KEYWORD

nonn,tabf

AUTHOR

Leroy Quet, Dec 20 2007

EXTENSIONS

More terms from Emeric Deutsch, Jan 05 2008

STATUS

approved

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Last modified October 14 07:31 EDT 2019. Contains 327995 sequences. (Running on oeis4.)