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A119959 p^2-p+1 central polygonal numbers with prime indices A002061(prime(n)). 7
3, 7, 21, 43, 111, 157, 273, 343, 507, 813, 931, 1333, 1641, 1807, 2163, 2757, 3423, 3661, 4423, 4971, 5257, 6163, 6807, 7833, 9313, 10101, 10507, 11343, 11773, 12657, 16003, 17031, 18633, 19183, 22053, 22651, 24493, 26407, 27723, 29757, 31863 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Prime terms belong to A074268, which is a subset of A002383, A087126, A034915, A085104.

In every interval of prime(n)^2 integers, a(n) is the number that are not divisible by prime(n) plus the number that are divisible by prime(n)^2. - Peter Munn, Dec 12 2020

LINKS

Table of n, a(n) for n=1..41.

FORMULA

a(n) = prime(n)^2 - prime(n) + 1.

a(n) = A036689(n)+1. - R. J. Mathar, Aug 13 2019

MATHEMATICA

Table[Prime[n]^2-Prime[n]+1, {n, 1, 100}]

CROSSREFS

Cf. A002061, A074268, A002383, A087126, A034915, A085104, A083558.

Sequence in context: A097162 A128402 A018689 * A329114 A018712 A183936

Adjacent sequences:  A119956 A119957 A119958 * A119960 A119961 A119962

KEYWORD

nonn

AUTHOR

Alexander Adamchuk, Aug 02 2006

STATUS

approved

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Last modified July 29 06:21 EDT 2021. Contains 346340 sequences. (Running on oeis4.)