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A139081 a(n) = (largest prime power dividing n) + (largest prime power dividing (n+1)). 3
3, 5, 7, 9, 8, 10, 15, 17, 14, 16, 15, 17, 20, 12, 21, 33, 26, 28, 24, 12, 18, 34, 31, 33, 38, 40, 34, 36, 34, 36, 63, 43, 28, 24, 16, 46, 56, 32, 21, 49, 48, 50, 54, 20, 32, 70, 63, 65, 74, 42, 30, 66, 80, 38, 19, 27, 48, 88, 64, 66, 92, 40, 73, 77, 24, 78, 84, 40, 30 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The largest prime-power dividing 12 is 4. The largest prime power dividing 13 is 13. So a(12) = 4+13 = 17.

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

FORMULA

a(n) = A034699(n) + A034699(n+1). [From Franklin T. Adams-Watters, Apr 09 2009]

MATHEMATICA

With[{c=Table[Max[#[[1]]^#[[2]]&/@FactorInteger[n]], {n, 70}]}, Total/@ Partition[ c, 2, 1]] (* Harvey P. Dale, Nov 18 2014 *)

PROG

Contribution from Franklin T. Adams-Watters, Apr 09 2009: (Start)

(PARI) maxpp(n)=local(m, r, pp); m=factor(n); r=1; for(i=1, matsize(m)[1], pp=m[i, 1]^m[i, 2]; if(pp>r, r=pp)); r

vector(80, i, maxpp(i)+maxpp(i+1)) (End)

CROSSREFS

Cf. A139082, A139083.

Sequence in context: A317509 A139083 A252002 * A196189 A206543 A274988

Adjacent sequences:  A139078 A139079 A139080 * A139082 A139083 A139084

KEYWORD

nonn

AUTHOR

Leroy Quet, Apr 07 2008

EXTENSIONS

More terms from Franklin T. Adams-Watters, Apr 09 2009

Definition clarified by Harvey P. Dale, Nov 18 2014

STATUS

approved

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Last modified May 22 10:55 EDT 2022. Contains 353949 sequences. (Running on oeis4.)