A079717 Subminimal numbers, from minimal numbers by analogy with subfactorials.

0, 1, 1, 2, 4, 6, 9, 13, 18, 22, 24, 44, 53, 66, 71, 88, 132, 212, 265, 309, 331, 353, 377, 464, 477, 618, 927, 1059, 1130, 1324, 1507, 1854, 1907, 2318, 2384, 2472, 2781, 3390, 3708, 4521, 5297, 5562, 5651, 7416, 9271, 9535, 10198, 11919, 13562, 16223, 16687, 16952, 17164, 18541, 20395, 22249

Offset

1,4

Links

Table of n, a(n) for n=1..56.

M. J. Halm, Sequences

Formula

a(n) = floor(A007416(n)/e + 1/2).

Example

a(6) = 6 because the 6th minimal number is 16 and floor(16/e + 1/2) = 6.

Mathematica

lim = 10^5; s = DivisorSigma[0, Range@ lim]; t = Select[Most@ Union[First@ FirstPosition[s, #] & /@ Range@ 200], # <= lim &]; Table[Floor[t[[n]]/E + 1/2], {n, 56}] (* Michael De Vlieger, Dec 20 2015, Version 10 *)

Prog

(PARI) is_a007416(n)=my(d=numdiv(n)); for(i=1, n-1, if(numdiv(i)==d, return(0))); 1;
for(n=1, 1e4, if(is_a007416(n), print1(floor(n/exp(1) + 1/2), ", "))); \\ Altug Alkan, Dec 20 2015

Crossrefs

Cf. A000166, A007416.

Sequence in context: A006697 A294860 A183920 * A247179 A319158 A175780

Adjacent sequences: A079714 A079715 A079716 * A079718 A079719 A079720

Keyword

nonn

Author

Michael Joseph Halm, Feb 17 2003

Extensions

More terms from Michael De Vlieger, Dec 20 2015

Status

approved