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A095702 Smallest "n-augmented" amicable number: the smallest positive integer k such that m = sigma(k) - k + n > k and k = sigma(m) - m + n, where sigma(k) is the sum of the divisors of k. 3
220, 6160, 24, 180, 20, 6, 224, 2632, 40, 10, 16, 28, 340, 14, 15, 42, 66, 3696, 208, 20, 21, 54, 264, 24, 68, 26, 88, 120, 102, 30, 4030, 56, 33, 34, 35, 60, 110, 38, 280, 40, 354, 66, 476, 44, 130, 46, 408, 92, 1276, 96, 51, 52, 354, 78, 55, 120, 57, 58, 852, 60, 170 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Amiram Eldar, Table of n, a(n) for n = 0..10000

EXAMPLE

a(1)= 6160 because sigma(6160)-6160+1 == 11697, sigma(11697)-11697+1 == 6160 and 6160 is the smallest integer for which this holds.

MATHEMATICA

a[n_] := Module[{k = n + 1, s}, While[( s = DivisorSigma[1, k] - k + n) <= k || DivisorSigma[1, s] - s + n != k, k++]; k]; Array[a, 61, 0] (* Amiram Eldar, Dec 24 2020 *)

PROG

(PARI) for(g=0, 60, x=g+1; while(1, a=sigma(x)-x+g; if((a-x)*a, if(sigma(a)-a+g==x, print1(x, ", "); break)); x+=1))

CROSSREFS

Cf. A000203, A002025, A002046, A007992, A015630.

Sequence in context: A055663 A333139 A022042 * A271674 A107506 A140918

Adjacent sequences:  A095699 A095700 A095701 * A095703 A095704 A095705

KEYWORD

nonn

AUTHOR

Jack Brennen, Jul 06 2004

STATUS

approved

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Last modified December 4 15:36 EST 2021. Contains 349526 sequences. (Running on oeis4.)