login
A343456
Indices k for which A343376(k+1) = A343376(k)/k.
5
1, 5, 10, 22, 31, 32, 43, 47, 57, 86, 89, 116, 134, 140, 144, 264, 283, 297, 317, 336, 355, 395, 465, 506, 562, 597, 609, 731, 737, 740, 765, 767, 772, 915, 1130, 1153, 1248, 1298, 1381, 1398, 1410, 1423, 1456, 1460, 1478, 1485, 1513, 1517, 1532, 1597, 1631, 1786
OFFSET
1,2
COMMENTS
The corresponding values of A343376(k+1) can be found in A343457.
LINKS
EXAMPLE
1 is a term since A343376(2) = 1 = A343376(1)/1.
5 is a term since A343376(6) = 1 = A343376(5)/5.
10 is a term since A343376(11) = 2 = A343376(10)/10.
22 is a term since A343376(23) = 94 = A343376(22)/22.
31 is a term since A343376(32) = 1504 = A343376(31)/31.
MAPLE
a:= proc(n) option remember; local q; `if`(n<2, n,
`if`(irem(a(n-1), n-1, 'q')=0, q, a(n-1)+a(n-2)))
end:
q:= n-> is(a(n+1)=a(n)/n):
select(q, [$1..2000])[]; # Alois P. Heinz, Apr 23 2021
MATHEMATICA
Block[{a = {0, 1}, b = {}}, Do[If[Mod[#, i] == 0, AppendTo[a, #/i]; AppendTo[b, i], AppendTo[a, # + a[[-2]] ]] &@ a[[-1]], {i, 2^11}]; b] (* Michael De Vlieger, Apr 22 2021 *)
PROG
(PARI) lista(nn) = {my(va = vector(nn)); va[1] = 1; for (n=2, nn, if (va[n-1] % (n-1), va[n] = va[n-1] + va[n-2], va[n] = va[n-1]/(n-1)); ); va; } \\ A343376
listk(nn) = {my(va = lista(nn)); for (k=1, nn-1, if (va[k]/k == va[k+1], print1(k, ", ")); ); } \\ Michel Marcus, Apr 20 2021
CROSSREFS
Sequence in context: A255150 A266580 A271257 * A087746 A064694 A264147
KEYWORD
nonn
AUTHOR
Timothy L. Tiffin, Apr 15 2021
EXTENSIONS
More terms from Michel Marcus, Apr 20 2021
STATUS
approved