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A307187 Numbers n such that A095112(n)/n sets a new record. 2
1, 2, 4, 6, 8, 12, 24, 48, 60, 120, 240, 360, 720, 1440, 1680, 2520, 5040, 10080, 15120, 20160, 30240, 50400, 55440, 110880, 166320, 221760, 332640, 665280, 1108800, 1330560, 1441440, 1663200, 2882880, 3326400, 4324320, 7207200, 8648640, 14414400, 17297280 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

n is in the sequence iff n is in position n in row n of A307081; in other words, iff A307088(n) = n.

LINKS

Table of n, a(n) for n=1..39.

EXAMPLE

With f(n) = A095112(n)/n,

f(1) = 0, new record, so 1 is in the sequence;

f(2) = 1/2, new record, so 2 is in the sequence;

f(3) = 1/3;

f(4) = 1/2 + 1/4 = 3/4, new record, so 4 is in the sequence;

f(5) = 1/5;

f(6) = 1/2 + 1/3 = 5/6, new record, so 6 is in the sequence;

etc.

PROG

(PARI)

f(n)={my(s=0, T); T=factorint(n); for(i=1, #T[, 1], for(j=1, T[i, 2], s+=1/T[i, 1]^j)); s}

prog(n)={my(V, v, j); V=List(); for(k=1, n, v=f(k)+0.; j=setsearch(V, v, 1); if(j==k, print1(k, ", ")); if(j==0, print("err"); return, listinsert(V, v, j)))}

CROSSREFS

Cf. A095112, A307081, A307088.

Sequence in context: A301414 A333953 A333963 * A340014 A001217 A131885

Adjacent sequences:  A307184 A307185 A307186 * A307188 A307189 A307190

KEYWORD

nonn

AUTHOR

Luc Rousseau, Mar 28 2019

STATUS

approved

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Last modified May 12 17:19 EDT 2021. Contains 343829 sequences. (Running on oeis4.)