A354994 Numbers k such that A344005(d) < A344005(k) for all proper divisors d of k.

1, 3, 4, 5, 7, 8, 9, 11, 13, 15, 16, 17, 19, 23, 24, 25, 27, 28, 29, 31, 32, 33, 35, 37, 40, 41, 43, 44, 45, 47, 49, 51, 53, 59, 60, 61, 63, 64, 65, 67, 69, 71, 73, 76, 77, 79, 81, 83, 84, 85, 87, 88, 89, 91, 92, 95, 96, 97, 99, 101, 103, 104, 107, 108, 109, 112, 113, 115, 117, 119, 121, 123, 124, 125, 127, 128, 131

Offset

1,2

Links

Table of n, a(n) for n=1..77.

Mathematica

s[n_] := Module[{m = 1}, While[!Divisible[m*(m + 1), n], m++]; m]; q[n_] := Module[{sn = s[n]}, DivisorSum[n, If[s[#] < sn, 0, 1] &, # < n &] == 0]; Select[Range[150], q] (* Amiram Eldar, Jun 17 2022 *)

Prog

(PARI)
A344005(n) = for(m=1, oo, if((m*(m+1))%n==0, return(m))); \\ From A344005
A354993(n) = { my(x=A344005(n)); fordiv(n, d, if(A344005(d)==x, return(d==n))); };
isA354994(n) = A354993(n);

Crossrefs

Positions of 1's in A354991 and in A354999.

Cf. A344005, A354993 (characteristic function).

Cf. also A344881, A345944.

Sequence in context: A247786 A330565 A139711 * A214585 A196036 A341416

Adjacent sequences: A354991 A354992 A354993 * A354995 A354996 A354997

Keyword

nonn

Author

Antti Karttunen, Jun 17 2022

Status

approved