cp's OEIS Frontend

A377781 First differences of A065514(n) = greatest number < prime(n) that is 1 or a prime-power.

%I A377781 #12 Nov 16 2024 22:15:52
%S A377781 1,2,1,4,2,5,1,2,8,2,3,5,4,2,6,4,6,5,3,4,2,8,2,6,8,4,2,4,2,16,3,3,6,2,
%T A377781 10,2,6,6,6,4,6,2,10,2,4,2,12,12,4,2,4,6,4,13,1,6,6,2,6,4,8,4,14,4,2,
%U A377781 4,14,12,4,2,4,8,6,6,6,4,6,8,4,8,10,2,10
%N A377781 First differences of A065514(n) = greatest number < prime(n) that is 1 or a prime-power.
%C A377781 Note 1 is a power of a prime but not a prime-power.
%t A377781 Differences[Table[NestWhile[#-1&,Prime[n]-1,#>1&&!PrimePowerQ[#]&],{n,100}]]
%Y A377781 Differences of A065514, which is the restriction of A031218 (differences A377782).
%Y A377781 The opposite is A377703 (restriction of A000015), differences of A345531.
%Y A377781 The opposite for nonsquarefree is A377784, differences of A377783.
%Y A377781 For nonsquarefree we have A378034, differences of A378032 (restriction of A378033).
%Y A377781 The opposite for squarefree is A378037, differences of A112926 (restriction of A067535).
%Y A377781 For squarefree we have A378038, differences of A112925 (restriction of A070321).
%Y A377781 A000040 lists the primes, differences A001223.
%Y A377781 A000961 and A246655 list the prime-powers, differences A057820.
%Y A377781 A024619 lists the non-prime-powers, differences A375735, seconds A376599.
%Y A377781 A361102 lists the non-powers of primes, differences A375708.
%Y A377781 Prime-powers between primes:
%Y A377781 - A053607 primes
%Y A377781 - A080101 count (exclusive)
%Y A377781 - A304521 by bits
%Y A377781 - A366833 count
%Y A377781 - A377057 positive
%Y A377781 - A377286 zero
%Y A377781 - A377287 one
%Y A377781 - A377288 two
%Y A377781 Cf. A001597, A007916, A008864, A053289, A120327, A343249, A375706, A377281, A377282, A377289.
%K A377781 nonn
%O A377781 1,2
%A A377781 _Gus Wiseman_, Nov 14 2024