A344883 Numbers k, not a power of prime, such that for all their proper divisors d A011772(d) < A011772(k).

12, 14, 15, 20, 22, 30, 33, 35, 38, 42, 44, 45, 46, 48, 51, 52, 54, 56, 62, 63, 65, 69, 70, 72, 76, 77, 80, 84, 85, 86, 87, 90, 91, 94, 95, 99, 102, 104, 108, 110, 112, 114, 115, 116, 117, 118, 119, 123, 130, 133, 134, 135, 140, 141, 142, 143, 145, 148, 152, 154, 158, 159, 161, 165, 166, 170, 172, 174, 175, 177, 180

Offset

1,1

Links

Table of n, a(n) for n=1..71.

Prog

(PARI)
A011772(n) = { if(n==1, return(1)); my(f=factor(if(n%2, n, 2*n)), step=vecmax(vector(#f~, i, f[i, 1]^f[i, 2]))); forstep(m=step, 2*n, step, if(m*(m-1)/2%n==0, return(m-1)); if(m*(m+1)/2%n==0, return(m))); }; \\ From A011772
A344880(n) = { my(x=A011772(n)); fordiv(n, d, if(A011772(d)==x, return(d==n))); };
isA344883(n) = ((n>1)&&!isprimepower(n)&&(1==A344880(n)));

Crossrefs

Cf. A011772, A344880.

Setwise difference A344881 \ A000961.

Sequence in context: A043701 A355148 A344980 * A290001 A371422 A080693

Adjacent sequences: A344880 A344881 A344882 * A344884 A344885 A344886

Keyword

nonn

Author

Antti Karttunen, Jun 01 2021

Status

approved