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A371168 Positive integers with fewer prime factors (A001222) than distinct divisors of prime indices (A370820).

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%I A371168 #6 Mar 16 2024 21:41:30
%S A371168 3,5,7,11,13,14,15,17,19,21,23,26,29,31,33,35,37,38,39,41,43,46,47,49,
%T A371168 51,52,53,55,57,58,59,61,65,67,69,70,71,73,74,76,77,78,79,83,85,86,87,
%U A371168 89,91,93,94,95,97,101,103,105,106,107,109,111,113,114,115
%N A371168 Positive integers with fewer prime factors (A001222) than distinct divisors of prime indices (A370820).
%C A371168 A prime index of n is a number m such that prime(m) divides n. The multiset of prime indices of n is row n of A112798.
%F A371168 A001222(a(n)) < A370820(a(n)).
%e A371168 The prime indices of 105 are {2,3,4}, and there are 3 prime factors (3,5,7) and 4 distinct divisors of prime indices (1,2,3,4), so 105 is in the sequence.
%e A371168 The terms together with their prime indices begin:
%e A371168      3: {2}      35: {3,4}      59: {17}        86: {1,14}
%e A371168      5: {3}      37: {12}       61: {18}        87: {2,10}
%e A371168      7: {4}      38: {1,8}      65: {3,6}       89: {24}
%e A371168     11: {5}      39: {2,6}      67: {19}        91: {4,6}
%e A371168     13: {6}      41: {13}       69: {2,9}       93: {2,11}
%e A371168     14: {1,4}    43: {14}       70: {1,3,4}     94: {1,15}
%e A371168     15: {2,3}    46: {1,9}      71: {20}        95: {3,8}
%e A371168     17: {7}      47: {15}       73: {21}        97: {25}
%e A371168     19: {8}      49: {4,4}      74: {1,12}     101: {26}
%e A371168     21: {2,4}    51: {2,7}      76: {1,1,8}    103: {27}
%e A371168     23: {9}      52: {1,1,6}    77: {4,5}      105: {2,3,4}
%e A371168     26: {1,6}    53: {16}       78: {1,2,6}    106: {1,16}
%e A371168     29: {10}     55: {3,5}      79: {22}       107: {28}
%e A371168     31: {11}     57: {2,8}      83: {23}       109: {29}
%e A371168     33: {2,5}    58: {1,10}     85: {3,7}      111: {2,12}
%t A371168 Select[Range[100],PrimeOmega[#]<Length[Union @@ Divisors/@PrimePi/@First/@If[#==1,{},FactorInteger[#]]]&]
%Y A371168 The opposite version is A370348 counted by A371171.
%Y A371168 The version for equality is A370802, counted by A371130, strict A371128.
%Y A371168 The RHS is A370820, for prime factors instead of divisors A303975.
%Y A371168 For divisors instead of prime factors on the LHS we get A371166.
%Y A371168 The complement is counted by A371169.
%Y A371168 The weak version is A371170.
%Y A371168 Partitions of this type are counted by A371173.
%Y A371168 Choosable partitions: A239312 (A368110), A355740 (A370320), A370592 (A368100), A370593 (A355529).
%Y A371168 A000005 counts divisors.
%Y A371168 A001221 counts distinct prime factors.
%Y A371168 A027746 lists prime factors, indices A112798, length A001222.
%Y A371168 A355731 counts choices of a divisor of each prime index, firsts A355732.
%Y A371168 Cf. A003963, A319899, A355737, A355739, A355741, A370808, A370814, A371127.
%K A371168 nonn
%O A371168 1,1
%A A371168 _Gus Wiseman_, Mar 16 2024