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 A308101 Numbers that set records for longest chains of "chained prime factors" of A308099. 2
 46, 1426, 120842, 12205042, 1257119326, 219043888774, 37904185920914, 8346405168610942, 1610856197541911806, 494532852645366924442, 159830762776306031303126, 63895498657264777378395106, 25160765901619915831898554178, 9890836489141547229675646151234 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Length          m       Distinct prime factors ------     ----------   ----------------------   2                46   {2,23}   3              1426   {2,23,31}   4            120842   {2,23,37,71}   5          12205042   {2,23,37,71,101}   6        1257119326   {2,23,37,71,101,103}   7      219043888774   {2,23,37,71,101,131,137}   8    37904185920914   {2,23,37,71,101,131,151,157}   9  8346405168610942   {2,23,37,71,101,131,151,181,191} LINKS MATHEMATICA ric[pr_, lp_, tg_] := Block[{cp}, If[tg==0, If[pr < curr, curr=pr], cp = NextPrime@ lp; While[pr cp^tg < curr, If[First@ IntegerDigits@ cp == Mod[lp, 10], ric[pr cp, cp, tg-1]]; cp = NextPrime@ cp]]]; a[n_] := Block[ {q = 2}, curr = Infinity; While[q^(n + 1) < curr, ric[q, q, n]; q = NextPrime@ q]; curr]; Array[a, 14] (* Giovanni Resta, Jun 25 2019 *) CROSSREFS Cf. A308099, A308252. Sequence in context: A103725 A332858 A264505 * A291129 A115608 A318044 Adjacent sequences:  A308098 A308099 A308100 * A308102 A308103 A308104 KEYWORD nonn,base AUTHOR Giorgos Kalogeropoulos, May 12 2019 EXTENSIONS a(6)-a(14) from Giovanni Resta, Jun 25 2019 STATUS approved

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Last modified December 1 11:35 EST 2021. Contains 349429 sequences. (Running on oeis4.)