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A249342
Position of the first occurrence of n-th noncomposite number, A008578(n), in A249337; positions of records in A249072.
4
1, 2, 6, 13, 20, 39, 45, 70, 80, 97, 121, 145, 193, 240, 257, 296, 322, 379, 400, 432, 481, 490, 532, 566, 632, 715, 760, 766, 807, 835, 878, 1067, 1104, 1209, 1215, 1369, 1414, 1468, 1514, 1540, 1605, 1683, 1706, 1853, 1871, 1905, 1935, 2116, 2276, 2293, 2304, 2343
OFFSET
1,2
FORMULA
For all n >= 1:
A249337(a(n)) = A008578(n).
A249072(a(n)) = n-1.
For all n >= 2:
a(n) = A249341(n) - 1.
PROG
(Scheme, with Antti Karttunen's IntSeq-library, two alternative definitions)
(define A249342 (MATCHING-POS 1 1 (lambda (n) (or (= 1 n) (and (= 1 (A249337 (+ 1 n))) (prime? (A249337 n)))))))
(define A249342 (RECORD-POS 1 1 A249072))
CROSSREFS
After the initial term, one less than A249341.
Sequence in context: A030416 A353588 A353971 * A006284 A048072 A215246
KEYWORD
nonn
AUTHOR
Antti Karttunen, Oct 26 2014
STATUS
approved