A365619 a(n) is the least integer k such that A366110(k) = n, or 0 if there is no such k.
0, 0, 0, 0, 0, 454, 0, 13, 0, 0, 0, 19, 0, 16, 0, 17, 15, 22, 6, 0, 0, 0, 0, 0, 0, 0, 0, 23, 0, 396, 0, 0, 0, 46, 0, 148, 40, 0, 8, 0, 0, 652, 0, 15980, 0, 0, 0, 25, 0, 0, 0, 0, 0, 50, 0, 0, 0, 0, 0, 136, 0, 0, 0, 27, 0, 64, 0, 0, 0, 100, 0, 29, 21, 0, 0, 0, 0, 15574, 0, 0, 0, 0, 0, 346
Offset: 1
Keywords
Links
- Michel Marcus, Table of n, a(n) for n = 1..10000
Programs
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PARI
lista(ns) = my(nn=100); my(vs = vector(ns, k, [])); forcomposite (i=1, (ns/2)^2, my(x=sigma(i)-i); if (x <= ns, if (#vs[x] <= 1, vs[x] = concat(vs[x], i), vs[x][2] = i));); my(v = vector(nn)); for (i=1, #vs, if (#vs[i] > 1, my(d = vecmax(vs[i])-vecmin(vs[i])); if ((d<=nn) && (!v[d] || (v[d]>i)), v[d] = i););); v; lista(2*10^4)
Comments