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A125286 a(0)=1. a(n) = a(n-1) + (the largest term among {a(0),a(1),...a(n-1)} that has the same number of positive divisors as n). 0
1, 2, 4, 6, 10, 12, 22, 24, 46, 50, 96, 98, 196, 198, 244, 290 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

a(16) does not exist because no earlier term has exactly 5 divisors. However, arbitrary modifications of the sequence's definition (such as letting a(n) = a(n-1) + 0 if no earlier term has the same number of divisors as n, or letting a(n) = a(n-1) + the largest earlier term with at most n divisors, etc.) would allow the sequence to be infinite in length.

LINKS

Table of n, a(n) for n=0..15.

EXAMPLE

9 has 3 divisors. So a(9) = a(8) + the largest earlier term with 3 divisors. a(3) = 4 is the only earlier term with 3 divisors, so a(9) = a(8) + 4 = 50.

CROSSREFS

Sequence in context: A133871 A068514 A074645 * A045963 A128169 A095923

Adjacent sequences:  A125283 A125284 A125285 * A125287 A125288 A125289

KEYWORD

fini,full,nonn

AUTHOR

Leroy Quet, Jan 26 2007

STATUS

approved

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Last modified February 24 04:36 EST 2020. Contains 332197 sequences. (Running on oeis4.)