A078398 a(1) = 1; a(n) for n > 1 is the smallest multiple of a(n-1) that begins with n concatenations of n.

1, 22, 33308, 444428644, 55555358214576, 66666652078924058304, 777777763142968864369469376, 88888888549672607030171696176233216, 99999999973937237107633586318949152704932864

Offset

1,2

Links

Table of n, a(n) for n=1..9.

Prog

(PARI) {print1(a=1, ", "); for(n=2, 9, k=floor(log(a)/log(10))+1; v=Str(n); for(i=2, n, v=concat(v, Str(n))); s=eval(v); t=s+1; m=floor(log(s)/log(10))+1; d=k-m; s=s*10^d; t=t*10^d; b=1; j=d; while(b>0, q=floor(s/a); while(b>0&&(p=q*a)<t, if(p>=s, print1(p, ", "); b=0, q++)); s=10*s; t=10*t); a=p)}

Crossrefs

Cf. A078399.

Sequence in context: A232847 A191946 A221639 * A280812 A060619 A362902

Adjacent sequences: A078395 A078396 A078397 * A078399 A078400 A078401

Keyword

base,nonn

Author

Amarnath Murthy, Nov 26 2002

Extensions

Edited and extended by Klaus Brockhaus, Dec 04 2002

Status

approved