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A037280 If n is composite replace n with the concatenation of its nontrivial divisors [ A037279 ] then divide out any factors of 2. 1
1, 1, 3, 1, 5, 23, 7, 3, 3, 25, 11, 1173, 13, 27, 35, 31, 17, 2369, 19, 12255, 37, 211, 23, 586703, 5, 213, 39, 12357, 29, 23561015, 31, 1551, 311, 217, 57, 117345609, 37, 219, 313, 6145255, 41, 23671421, 43, 120561, 35915, 223, 47, 2933515203, 7, 251025, 317 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..51.

EXAMPLE

Divisors of 12 are 1,2,3,4,6,12, so 12 -> 2346 = 2*1173 -> 1173 = a(12).

MAPLE

with(numtheory):ds:=proc(s) local j: RETURN(add(s[j]*10^(j-1), j=1..nops(s))):end: a:=proc(n) options remember: local d, i, l, m: if n<3 then RETURN(1) else if not isprime(n) then d:=divisors(n): l:=nops(d): m:=ds([seq(op(convert(d[l-i+1], base, 10)), i=2..l-1)]): RETURN(m/piecewise(m mod 2=1, 1, 2^(ifactors(m)[2][1][2]))) else RETURN(n) fi fi: end; seq(a(n), n=1..70); # C. Ronaldo

CROSSREFS

Cf. A037279.

Sequence in context: A039512 A140825 A265981 * A324204 A168611 A133397

Adjacent sequences:  A037277 A037278 A037279 * A037281 A037282 A037283

KEYWORD

nonn,easy,base

AUTHOR

N. J. A. Sloane

EXTENSIONS

More terms from Erich Friedman

STATUS

approved

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Last modified March 2 06:37 EST 2021. Contains 341744 sequences. (Running on oeis4.)