1,1

Also called Smarandache permutation sequence.

M. Le, Perfect Powers in the Smarandache Permutation Sequence, Smarandache Notions Journal, Vol. 10, No. 1-2-3, 1999, 148-149.

F. Smarandache, "Only Problems, not Solutions!", Xiquan Publ., Phoenix-Chicago, 1993.

M. L. Perez et al., eds., Smarandache Notions Journal

F. Smarandache, Only Problems, Not Solutions!

a(n)=a1+a2+a3 where a1=floor[a(n-1)/(10^d)]*10^floor[1+log10(a2)], a2={(2*n-1)*10^floor[1+log10(2*n)]+2*n}*10^floor[1+log10(a3)], a3=a(n-1)-floor[a(n-1)/(10^d)]*10^floor(d), d={floor[1+log10(a(n-1))]+[1+(-1)^floor(1+log10(2*(n-1)))]/2}/2+w, w={floor[1+log10(2*n-1)]-1-(1-(-1)^(floor[1+log10(2*n-1)]-1))/2}/2. - Paolo P. Lava (ppl(AT)spl.at), Jun 17 2008

P:=proc(n) local a, a1, a2, a3, d, i, w; a:=12; print(a); for i from 2 by 1 to n do w:=(floor(evalf(1+log10(2*i-1), 1000))-1-(1-(-1)^(floor(evalf(1+log10(2*i-1), 1000))-1))/2)/2; d:=(floor(evalf(1+log10(a), 1000))+(1+(-1)^floor(evalf(1+log10(2*(i-1)), 1000)))/2)/2+w; a3:=a-floor(evalf(a/(10^d), 1000))*10^floor(evalf(d, 1000)); a2:=((2*i-1)*10^floor(evalf(1+log10(2*i), 1000))+2*i)*10^floor(evalf(1+log10(a3), 1000)); a1:=floor(evalf(a/(10^d), 1000))*10^floor(evalf(1+log10(a2), 1000)); a:=a1+a2+a3; print(a); od; end: P(1000); - Paolo P. Lava (ppl(AT)spl.at), Jun 17 2008

Sequence in context: A133461 A071309 A067108 this_sequence A015512 A004145 A145835

Adjacent sequences: A007940 A007941 A007942 this_sequence A007944 A007945 A007946

nonn,base

R. Muller