A360129 - OEIS

A360129

Numbers k such that A360119(k) > 1, but which have no divisors d > 1 such that d+1 is also a divisor.

572, 1144, 1292, 1768, 2288, 2584, 2590, 3496, 3596, 4030, 4576, 4930, 6292, 6992, 7052, 7192, 7436, 8050, 8170, 8246, 9044, 9152, 9212, 9430, 9724, 9758, 10868, 11408, 12136, 12584, 12950, 13984, 14104, 14212, 14384, 14396, 14872, 15370, 16168, 16492, 16588, 16796, 17066, 17168, 17732, 18130, 18304

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..47.

FORMULA

{k | A088722(k) = 0 and A360119(k) > 1}.

PROG

(PARI)

A360119(n) = { my(d=divisors(n), erot=vecsort(vector(#d-1, k, d[k+1] - d[k])), s=#d); for(i=1, #erot, if(n%erot[i], s--, if(1==i || erot[i]!=erot[i-1], s--))); (s); };

A360128(n) = !sumdiv(n, d, (d>1)&&!(n%(d+1)));

isA360129(n) = (A360128(n)&&(A360119(n)>1));

CROSSREFS

Subsequence of A088725.

Cf. A088722, A360119, A360128.

Sequence in context: A175989 A252640 A252641 * A252632 A263813 A231244

Adjacent sequences: A360126 A360127 A360128 * A360130 A360131 A360132

KEYWORD

nonn

AUTHOR

Antti Karttunen, Feb 20 2023

STATUS

approved