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

Author

J. Lowell, Sep 02 2008

Keywords

• nonn

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

Crossrefs

Cf. A066839, A141037.

Programs

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

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

Formula

a(n) = A066839(A141037(n)).

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