Search: id:A063384 Results 1-1 of 1 results found. %I A063384 %S A063384 7,17,117,913,1183,1391,13107,51257,151257,381397,577661,4911789, %T A063384 29116879,112646989,536920981,1928258999,11928258999,25227472837, %U A063384 46275452231,212892173679,370964057893,1859199550327,5593332415439 %N A063384 a(1) = 7, a(n) = concatenation of two closest factors of a(n-1) whose product equals a(n-1) or if a(n-1) is a prime then the concatenation of 1 and a(n-1). %t A063384 f[ n_Integer ] := (d = Divisors[ n ]; l = Length[ d ]; If[ EvenQ[ l ], ToExpression[ ToString[ d[[ l/2 ] ]] <> ToString[ d[[ l/2 + 1 ]] ]], ToExpression[ ToString[ d[[ l/2 + .5 ] ]] <> ToString[ d[[ l/ 2 + .5 ] ]] ]] ); NestList[ f, 7, 25 ] %Y A063384 Cf. A003681, A062094 and A062095. %Y A063384 Sequence in context: A092340 A068172 A067185 this_sequence A165246 A118108 A147643 %Y A063384 Adjacent sequences: A063381 A063382 A063383 this_sequence A063385 A063386 A063387 %K A063384 base,nonn %O A063384 1,1 %A A063384 Robert G. Wilson v (rgwv(AT)rgwv.com), Aug 09 2001 Search completed in 0.001 seconds