A143837 a(n) = A066839(A141037(n)).
1, 3, 4, 6, 7, 10, 11, 16, 21, 24, 26, 39, 45, 52, 66, 73, 93, 99, 102, 105, 110, 111, 118, 153, 180, 194, 240, 251, 301, 331, 435, 479, 487, 504, 513, 518, 525, 546, 748, 753, 921, 993, 1202, 1285, 1352, 1600, 1716, 1869, 1902, 2221, 2477, 2601, 2640, 2807
Offset: 1
Keywords
Examples
The value of 16 in this sequence corresponds to 1+2+3+4+6 = 16 with 1, 2, 3, 4 and 6 being the divisors of 36 <= sqrt(36).
Links
- Amiram Eldar, Table of n, a(n) for n = 1..250
Programs
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Maple
A066839 := proc(n) a := 0 ; for k in numtheory[divisors](n) do if k^2 <= n then a := a+k ; fi; od: a ; end: A143837 := proc() rec := -1; for n from 1 do r := A066839(n) ; if r > rec then printf("%d, ",r) ; rec := r; fi; od: end: A143837() ; # R. J. Mathar, Nov 03 2008
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PARI
lista(nn) = {my(ms = 0); for (n=1, nn, sqn = sqrt(n); s = sumdiv(n, d, d*(d<=sqn)); if (s > ms, print1(s, ", "); ms = s););} \\ Michel Marcus, Oct 05 2015
Extensions
More terms from R. J. Mathar, Nov 03 2008
Name edited by Jon E. Schoenfield at the suggestion of Joerg Arndt, Oct 12 2015
Comments