A278520 -id:A278520 - cp's OEIS frontend

A280488 a(n) = n / A280489(n) = n / gcd(n,A241909(n)).

1, 1, 3, 4, 5, 2, 7, 8, 3, 10, 11, 12, 13, 14, 5, 16, 17, 6, 19, 4, 7, 22, 23, 24, 25, 26, 27, 28, 29, 2, 31, 32, 11, 34, 35, 36, 37, 38, 13, 40, 41, 14, 43, 44, 9, 46, 47, 48, 49, 10, 17, 52, 53, 18, 55, 8, 19, 58, 59, 12, 61, 62, 63, 64, 65, 22, 67, 68, 23, 14, 71, 72, 73, 74, 5, 76, 77, 26, 79, 80, 81, 82, 83, 12, 85, 86, 29, 88, 89, 30, 91, 92, 31

Offset: 1

Antti Karttunen, Jan 09 2017

nonn

Antti Karttunen, Table of n, a(n) for n = 1..8192

Cf. A241909, A280489, A280490, A278520.

Scheme
```
(define (A280488 n) (/ n (A280489 n)))
```

a(n) = n / A280489(n).

A280490 a(n) = n / A280491(n) = n / gcd(n,A122111(n)).

Original entry on oeis.org

1, 1, 3, 4, 5, 1, 7, 8, 1, 5, 11, 6, 13, 7, 5, 16, 17, 6, 19, 1, 7, 11, 23, 12, 25, 13, 27, 7, 29, 1, 31, 32, 11, 17, 35, 12, 37, 19, 13, 10, 41, 7, 43, 11, 9, 23, 47, 24, 49, 10, 17, 13, 53, 54, 55, 1, 19, 29, 59, 10, 61, 31, 63, 64, 65, 11, 67, 17, 23, 7, 71, 24, 73, 37, 1, 19, 77, 13, 79, 20, 81, 41, 83, 1, 85, 43, 29, 11, 89, 9, 91, 23, 31, 47, 95, 48, 97

Offset: 1

Antti Karttunen, Jan 09 2017

nonn

Antti Karttunen, Table of n, a(n) for n = 1..8192

Cf. A088902 (the positions of 1's).

Cf. A122111, A280491, also A278520, A280488.

Scheme
```
(define (A280490 n) (/ n (A280491 n)))
```

a(n) = n / A280491(n) = n / gcd(n,A122111(n)).

A286456 Compound filter: a(n) = P(A056239(n), A243503(n)), with a(1) = 0, where P(n,k) is sequence A000027 used as a pairing function.

Original entry on oeis.org

0, 1, 5, 5, 13, 18, 25, 13, 19, 40, 41, 40, 61, 71, 41, 25, 85, 41, 113, 83, 72, 111, 145, 71, 42, 160, 42, 142, 181, 84, 221, 41, 112, 218, 73, 72, 265, 285, 161, 142, 313, 143, 365, 217, 85, 361, 421, 111, 74, 85, 219, 308, 481, 73, 113, 238, 286, 446, 545, 143, 613, 540, 144, 61, 162, 218, 685, 415, 362, 144, 761, 112, 841, 643, 86, 538, 114, 309, 925, 217

Offset: 1

Antti Karttunen, May 14 2017

nonn

Antti Karttunen, Table of n, a(n) for n = 1..8192 (computed by using the b-files of A056239 and A243503)
Eric Weisstein's World of Mathematics, Pairing Function

Cf. A000027, A056239, A243503, A278520, A286454, A286455.

(define (A286456 n) (if (= 1 n) 0 (* (/ 1 2) (+ (expt (+ (A056239 n) (A243503 n)) 2) (- (A056239 n)) (- (* 3 (A243503 n))) 2))))

a(1) = 0 and for n > 1, a(n) = (1/2)*(2 + ((A056239(n)+A243503(n))^2) - A056239(n) - 3*A243503(n)).

cp's OEIS Frontend

A280488 a(n) = n / A280489(n) = n / gcd(n,A241909(n)).

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A280490 a(n) = n / A280491(n) = n / gcd(n,A122111(n)).

Views

Author

Keywords

Links

Crossrefs

Programs

Scheme

Formula

A286456 Compound filter: a(n) = P(A056239(n), A243503(n)), with a(1) = 0, where P(n,k) is sequence A000027 used as a pairing function.

Views

Author

Keywords

Links

Crossrefs

Programs

Scheme

Formula