A353862 - OEIS

A353862

Greatest run-sum of the prime indices of n.

0, 1, 2, 2, 3, 2, 4, 3, 4, 3, 5, 2, 6, 4, 3, 4, 7, 4, 8, 3, 4, 5, 9, 3, 6, 6, 6, 4, 10, 3, 11, 5, 5, 7, 4, 4, 12, 8, 6, 3, 13, 4, 14, 5, 4, 9, 15, 4, 8, 6, 7, 6, 16, 6, 5, 4, 8, 10, 17, 3, 18, 11, 4, 6, 6, 5, 19, 7, 9, 4, 20, 4, 21, 12, 6, 8, 5, 6, 22, 4, 8

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OFFSET

1,3

COMMENTS

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.

A run-sum of a sequence is the sum of any maximal consecutive constant subsequence.

LINKS

Table of n, a(n) for n=1..81.

EXAMPLE

The prime indices of 72 are {1,1,1,2,2}, with run-sums {3,4}, so a(72) = 4.

MATHEMATICA

Table[Max@@Cases[FactorInteger[n], {p_, k_}:>PrimePi[p]*k], {n, 100}]

CROSSREFS

Positions of first appearances are A008578.

For binary expansion we have A038374, least A144790.

For run-lengths instead of run-sums we have A051903.

Distinct run-sums are counted by A353835, weak A353861.

The least run-sum is given by A353931.

A001222 counts prime factors, distinct A001221.

A005811 counts runs in binary expansion.

A056239 adds up prime indices, row sums of A112798 and A296150.

A124010 gives prime signature, sorted A118914.

A300273 ranks collapsible partitions, counted by A275870.

A304442 counts partitions with all equal run-sums, compositions A353851.

A353832 represents the operation of taking run-sums of a partition.

A353833 ranks partitions with all equal run sums, nonprime A353834.

A353838 ranks partitions with all distinct run-sums, counted by A353837.

A353840-A353846 pertain to partition run-sum trajectory.

Cf. A067340, A073093, A181819, A182857, A316413, A353836, A353839, A353848, A353852, A353866.

Sequence in context: A280338 A339147 A062821 * A338719 A296080 A180633

Adjacent sequences: A353859 A353860 A353861 * A353863 A353864 A353865

KEYWORD

nonn

AUTHOR

Gus Wiseman, May 23 2022

STATUS

approved