A352244 Positive integers that can be expressed in at least two ways as (x-y)*(x^3-y^3).

57456, 80752, 124852, 229957, 355072, 366471, 630667, 919296, 1193200, 1292032, 1316875, 1371136, 1823472, 1997632, 2036097, 2687607, 3679312, 4251871, 4653936, 5681152, 5821552, 5863536, 6540912, 8905456, 8984196, 10090672, 10113012, 10504375, 10532592, 10789632, 10921456, 14708736

Offset

1,1

Comments

Integers that appears at least twice in the A352242 triangle.

Links

David A. Corneth, Table of n, a(n) for n = 1..12994 (terms <= 10^14)

David A. Corneth, PARI program

Example

57456 is a term since it is A352242(17,5) as well as A352242(26,20).
A term (not necessarily the first) that occurs at least three times in A352242 is 1641000816 = A352242(221,65) = A352242(338,260) = A352242(1955,1943). - Robert Israel, May 17 2024

Prog

(PARI) row(n) = vector(n-1, k, (n-k)*(n^3-k^3));
lista(nn) = {my(list = List(), n=2); while (3*n*(n-1)+1 <= nn, my(rown = row(n)); for (k=1, #rown, if (rown[k] <= nn, listput(list, rown[k]))); n++; ); listsort(list); my(res = List()); for (n=1, #list, if (#select(x->(x==list[n]), list) > 1, if (!vecsearch(Vec(res), list[n]), listput(res, list[n]))); ); Vec(res); }
(PARI) \\ See PARI link

Crossrefs

Cf. A352242, A352243.

Sequence in context: A069335 A236152 A340434 * A233643 A166195 A031861

Adjacent sequences: A352241 A352242 A352243 * A352245 A352246 A352247

Keyword

nonn

Author

Michel Marcus, Mar 09 2022, after a suggestion from Vincent Thill

Status

approved