A222311 Leading diagonal of triangle in A222310.

1, 2, 3, 6, 5, 15, 105, 70, 1, 5, 33, 55, 65, 273, 1001, 1430, 17, 17, 969, 4845, 1785, 6545, 37145, 81719, 17, 1105, 3553, 969969, 672945, 81345, 955049953, 66786710, 33, 561, 385, 6545, 6105, 657305, 15873, 8544965, 1353, 268345, 61705, 329681, 650793, 24173705985, 3065857, 250538768183, 561, 33, 21945

Offset: 1

Author

N. J. A. Sloane, Feb 16 2013

Keywords

• nonn

Comments

See A222313 for the numbers that appear in this sequence.

Links

• N. J. A. Sloane, Table of n, a(n) for n = 1..500
• C. Cobeli and A. Zaharescu, Promenade around Pascal Triangle-Number Motives, Bull. Math. Soc. Sci. Math. Roumanie, Tome 56(104) No. 1, 2013, 73-98.
• Cristian Cobeli, Alexandru Zaharescu, A game with divisors and absolute differences of exponents, arXiv:1411.1334 [math.NT], 2014 (see page 12).
• Cristian Cobeli, Mihai Prunescu, Alexandru Zaharescu, A growth model based on the arithmetic Z-game, arXiv:1511.04315 [math.NT], 2015.

Crossrefs

Cf. A222310, A222313.

Programs

Mathematica

Join[r = {1}, Table[Reverse[r = FoldList[#1*#2/GCD[#1, #2]^2&, n, r]], {n, 2, 100}][[All, 1]]] (* Jean-François Alcover, Sep 04 2018, after Ivan Neretin in A222310 *)